Avian Influenza has become endemic in many parts of the word. In it's current form it has been around since 1997 and although thy virus types have changed, emergency response, management & control are still a hot issue. In this article published in 2006 in the US magazine Poultry Perspectives, the subject what to do during crisis situations is presented. The conclusions are still valid today and may help to prevent large-scale outbreaks

1. The 3 P’s of Avian Influenza:
Prevent, Plan, Practice 1
Is There a Monster in the
(Poultry) House? 2
AI Outbreak in Europe in 2003:
Lessons to Be Learned 4
Depopulation of Poultry Flocks
during Disease Outbreaks
and Other Catastrophic Events 9
Disposal Options for Avian
Influenza Flocks 10
Spring 2006 Volume 7, Number 1
Editor’s Note
The 3 P’s of Avian Influenza: Prevent,
Plan, Practice
These days everyone from the poultry industry wonders what may be heading
our way as birds start their migratory flight north to their breeding grounds.
Will this time bring the undesired virus? We cannot stop wild birds from flying
and carrying viruses with them, including AI. However, there are a few things
we can do that can be summarized as the 3 P’s of Avian Influenza: Prevent,
Plan, and Practice. Prevent any contact of wild birds with poultry and apply
very strict biosecurity measures to reduce the chances of an outbreak. Do not
wait until an outbreak occurs; establish a clear plan of action beforehand when
See 3 P’s on page 2
is published by the College of Agriculture and Natural Resources,
University of Maryland, College Park, Maryland.
EDITORS
Inma Estevez, Ph.D.
Roselina Angel, Ph.D.
Dept. of Animal and Avian Sciences
University of Maryland
College Park, MD 20742
HOW TO CONTACT US
Inma Estevez, Ph.D.
E-mail: iestevez@umd.edu
Tel: 301-405-5779
Fax: 301-314-9059
Roselina Angel, Ph.D.
E-mail: rangel@umd.edu
Tel: 301-405-8494
Fax: 301-314-9059
CONTRIBUTORS
Daniel R. Perez, PhD.
Assistant Professor
Department of Veterinary Medicine
University of Maryland, College Park
dperez@umd.edu
Harm Kiezebrink
Independent Expert in the Control of
Avian Influenza at the Farm Level
Adcare GmbH (Munich, Germany),
center@ad-care.com
Dr. Nathaniel L. Tablante
Extension Poultry Veterinarian
University of Maryland, College Park
nlt@umd.edu
Bud Malone
Extension Poultry Specialist
University of Delaware
malone@udel.edu
In This Issue

2. 2
you have time to think and design
the best strategies for effective con-
trol. And practice! Make sure you
have the opportunity to do a mock
trial to determine the effectiveness
of your plan of control. This issue of
Poultry Perspectives offers informa-
tion that can be used to comply with
the 3 P’s.
There is never going to be a better
time to work on a plan than RIGHT
NOW!
3 P’s from page 1
For the past year or so, the media
has flooded newspapers, radio and
television shows, and the Internet
with the fear that a new influenza
pandemic is looming over us. Is that
fear founded? When will the pan-
demic occur? I work with poultry all
the time—am I at risk of becoming
infected and dying? What can we
do to protect our poultry and our-
selves from the effects of this virus?
I will go over these questions in the
context of poultry avian species:
there are approaches that are easy to
implement and can stop the spread
of these viruses that can infect
people. I must point out, however,
that potentially pandemic strains
will continue to emerge from wild-
life avian hosts. The best weapon
we have to control the emergence
of these viruses is to adopt strict bio-
security measures, implement good
surveillance strategies, and learn
more about the risks of the disease
for animals and humans.
Avian influenza is a disease of
poultry, whose disease symptoms
vary from completely mild or
unnoticeable to a catastrophic
disease with a mortality rate that
can reach up to 100 percent in
some avian species. The natural
hosts of the virus are ducks,
shorebirds, and other species of wild
aquatic birds. In the natural hosts,
influenza infections cause almost
no disease signs and the infection is
established mostly in the intestinal
tract. The virus is excreted with
the feces into the water, promoting
a cycle of fecal-oral transmission.
Occasionally, the virus “jumps”
from wild birds to domestic
birds causing disease outbreaks
(sometimes briefly subclinical, and
then becoming more obvious as the
disease increases in virulence).
The surface of the virus contains
two major components, which are
the targets of antibodies generated
by the host’s immune system.
These two components are divided
into subtypes based on the ability
of antibodies to recognize them.
There are 16 subtypes of one of
the components known as HA or
hemagglutinin and 9 subtypes of
the other component, known as
NA or neuraminidase. Thus, the
nomenclature of influenza viruses
includes the subtype characteristics
of the virus. For example, the H5N1
viruses in Asia contain an HA of
subtype 5 and an NA of subtype
1. Both components are essential
for the survival of the virus, and
antibodies created against the HA
can prevent the virus from infecting
the cell.
In addition, influenza viruses
are named based on characteristics
of the host, the place of isolation,
some form of strain identification
code, and the last two digits of
the year of isolation. For example,
A/chicken/Hong Kong/YU562/01
(H5N1) is a type A H5N1 influenza
virus (all avian influenza viruses are
type A viruses; humans are affected
by types A and B), isolated from a
chicken in Hong Kong in 2001 and
identified as YU562. Because the
genome of influenza viruses is made
up by segments and co-infections in
birds are common, influenza viruses
with many different combinations
of HA and NA subtypes have been
isolated in nature. Only viruses of
the H5 and H7 subtypes are known
to cause high mortality in birds. All
other virus subtypes cause a milder
Is There a Monster in the (Poultry) House?
by Daniel R. Perez, PhD.

3. 3
form of disease affecting either the
intestinal or respiratory tracts, or
both.
Signs of disease may include
excess mucus, diarrhea, watery eyes,
and drops in egg production. The
more virulent forms of the disease
are accompanied by neurological
disorders and massive hemorrhages,
which are clearly noticeable as a
purple coloration on the combs and
feet. The time course of the infection
also varies greatly from a few days
to a sudden disease that kills the
birds in less than a day.
Accumulation of specific
mutations on the HA of the H5
and H7 subtypes results in the
emergence of strains with high
virulence and mortality; however,
mortality rates can vary greatly
among different avian species,
with the most frequently affected
being chickens and turkeys. It is not
known exactly which avian species
contribute to the emergence of these
highly pathogenic strains, although
both chickens and turkeys seem to
play a major role. Many disease
outbreaks in chickens and turkeys
have started with H5 or H7 subtypes
that were very mild, that sometimes
went undetected and later became
highly virulent.
Because many other intestinal or
respiratory diseases of poultry can
cause similar disease symptoms, we
cannot rely on disease symptoms
alone to diagnose avian influenza.
Thus, constant monitoring of the
flock is encouraged by submitting
serum, tracheal and cloacal swabs to
the diagnostic laboratory to perform
antibody tests and virus isolations.
The mild forms of the disease may
last only a few days, leaving only
a small window of opportunity to
detect the virus. Serum samples
should also be collected to analyze
the presence of antibodies against
the virus, which last much longer
and are easier to detect.
Several diagnostic companies are
developing tests that will allow the
detection of the virus or antibodies
to it at the farm level. These tests
are easy to use and very sensitive
and are currently pending USDA
approval. A word of caution must
be used here: If the test is positive,
it is most likely that avian influenza
is present in your flock; however,
the test will not indicate what HA
or NA subtype it is. A reliable
diagnostic laboratory test must be
performed to confirm the presence
and characteristics of the virus. On
the other hand, a negative test at the
farm level does not guarantee that
the flock is free of avian influenza.
Submission of samples to the lab
is strongly encouraged, even when
the flock appears perfectly healthy.
Making a habit of screening for
potential disease signs, excess
an Avian influenza virus from wild
birds are very low. Infection with
some viruses may be very localized
and not life-threatening: H7
infections, for example, can cause
conjunctivitis (pink eye) in humans.
Avian influenza viruses that become
adapted to domestic flocks are also
not likely to “jump” to humans.
However, the experience in Asia
has taught us that letting influenza
viruses circulate in domestic bird
species for extended periods can
lead to strains that become more
and more efficient at making the
“jump” to humans and other animal
species. Once again, being vigilant,
identifying potential disease signs,
and practicing strict biosecurity
measures provide greater protection
for you and your flock. The Animal
and Plant Health and Inspection
Services (APHIS) has an excellent
online resource called Biosecurity
for the Birds (http://www.aphis.
usda.gov/vs/birdbiosecurity/), which
provides extensive information about
biosecurity and other strategies for
protecting your flock and yourself.
You can also contact APHIS at toll-
free 1-866-536-7593. Additional
information about avian influenza
can be found at http://www.agnr.
umd.edu/aicap, which provides
information about the disease,
contains several educational
resources, and presents an overview
of several research projects currently
funded by the USDA on prevention
and control of avian influenza in
the U.S. (a newly updated version
of this web resource is expected by
mid-November).
The current H5N1 situation has
sounded the alarm in animal and
public health organizations at the
international and national levels.
The World Health Organization
speculates that it will take at least
two years before H5N1 viruses
are controlled in Asia. The list of
countries reporting outbreaks of
H5N1 HPAI continues to increase
despite the 160 million domestic
poultry that have died or been
culled in Asia to control the spread
of the disease. The estimated
“Because many other
intestinal or respiratory
diseases of poultry
can cause similar
disease symptoms,
we cannot rely on
disease symptoms alone
to diagnose Avian
Influenza.”
mortality, and taking samples for
laboratory analysis will achieve two
purposes: Both you and your flock
will be protected from spreading a
disease that can carry major animal
and public health implications.
Remember, not reporting the
presence of the virus in your flock
will most likely backfire on you.
Sooner or later, you and your flock
will be severely affected.
Am I and those in contact with
chickens and their products at risk
of becoming infected? Most avian
influenza viruses, regardless of the
subtype, do not infect humans. Avian
influenza viruses from wild birds are
so adapted to them that the chances
of humans becoming infected with

4. 44
economic losses to the Asian poultry
sector are approximately $10
billion, threatening the livelihood
of millions of people. Recent
findings suggested that migratory
aquatic birds might facilitate the
transmission of the H5N1 viruses,
and recent reports indicating the
presence of the virus in several
countries in Europe have confirmed
this assumption. Importation of
exotic birds is another way of
spreading the disease as the virus
has recently been reported in the
United Kingdom in imported birds.
There has to be a major effort
worldwide to strictly control the
movement of exotic birds between
countries, not only to control the
spread of avian influenza, but also
other known or unknown diseases.
Is the U.S. vulnerable? Imported
birds are strictly quarantined and
tested before they are allowed to
enter the U.S., so in this regard
the U.S. is protected. The U.S.
does not allow importation of live
commercial birds from Asia and
similar measures have been quickly
adopted for countries reporting avian
influenza. However, the virus could
potentially enter the U.S. through
migratory birds, smuggling of birds,
or through people. Keep your birds
in the house and do not let them
co-mingle with wild birds. Control
the access of other animal pests into
the poultry house. Do not let anyone
you do not know come close to your
poultry house.
Are these fears founded?
Absolutely. The fact that the virus
has managed to cross to humans
several times with significant
mortality and that all human
influenza pandemics have initiated
from an avian influenza virus,
put H5N1 viruses in the list of
potentially pandemic viruses. When
will the H5N1 pandemic occur? We
do not know. It may start tomorrow
or it may not happen in our lifetime;
however, we do need to be prepared
because a pandemic influenza
virus can emerge at any time. If the
previous 100 years gave us three
pandemics, how many are we going
to get in the next 100 years? As the
world prepares for the inevitable,
poultry farmers around the world
can be at the forefront in the control
of the disease and, thus, prevent the
emergence of pandemic influenza
strains at the amplification stage:
poultry species. In the research
arena, novel vaccine strategies and
faster and more sensitive diagnostic
tools will soon provide a number of
alternatives for the poultry sector to
combat the disease. In the future,
researchers will be able to predict
which viruses are more likely to be a
pandemic threat. However, it is only
going to be through the combined
efforts of poultry farmers, poultry
veterinarians, government agencies,
diagnosticians, and researchers that
the inevitable be made preventable.
AI Outbreak in Europe in 2003: Lessons to Be Learned
by Harm Kiezebrink
Introduction
In October 1997 the poultry world
was shocked by the news that avian
influenza (AI) had struck Asia for
the first time in decades. In Hong
Kong all poultry was culled within
days and the outbreak seemed to be
under control. But as we know now,
it did not disappear. The same H5N1
virus is currently rushing with dev-
astating force over the globe. Many
experts and governments tried to
warn about the necessity of control-
ling the disease to avoid potential
catastrophic consequences without
success. It is time to come back to
reality and stick to the facts, espe-
cially when it comes to preparing
the poultry industry for a possible
outbreak.

5. 5
Consequences for the
Industry
Avian influenza is not solely
a chicken disease. AI can also
affect other bird species as well as
humans. Nevertheless, the threat of
humans contracting AI has always
been shown to be directly linked to
poultry and the poultry industry.
This connection can be extremely
devastating for the industry, as
poultry consumption drops after
the appearance of AI. I will give an
example that shocked the farming
industry in Holland. A Dutch
animal welfare activist group who
are opposed to the commercial
poultry industry misused the link
between avian influenza and the
pandemic threat to human health
in a public campaign against the
poultry industry. In December 2005
the Dutch animal welfare activist
group, ‘Wakker dier’, began to
exploit general public fear about
the human implications of AI by
broadcasting a totally misleading
radio commercial with the slogan
“Slow down the virus, don’t eat
chicken.” Poultry farmers reacted
quickly, asking a judge to stop this
campaign immediately, but without
any success. In spite of poultry
producers’ arguments that AI in Asia
and Europe occurred only within
wildfowl and backyard farming and
that the ‘Wakker dier’ campaign was
based upon fragmented information
pulled out of context, the judge
concluded that ‘Wakker dier’ gave
sufficient “facts to justify” their
campaign. The judge rejected the
arguments and demands from the
poultry industry. The disintegrating
Dutch farming industry now faced
an unexpected drop in poultry
products just a few days before
Christmas.
How the Truth Became
So Distorted
News agencies start their reports
with this statement or one similar:
“Today it was confirmed that the
virus H5N1, the deadly virus that
under certain circumstances can
affect humans, has been found in
a population of migrating ducks.
The export of all poultry products
is directly banned.” I have heard
these sentences over and over again,
especially in the last couple of
weeks. The consequences are clear.
The public links the outbreak of
avian influenza directly to poultry,
because of the ban on poultry
products. As a consequence, the
consumption of poultry has dropped
dramatically. In Romania, for
example, poultry consumption has
been reduced by 60 percent due
to media reports. When the public
panics the first victim is the poultry
industry. In a competitive market,
the poultry industry has a lot to
their own birds and they should
avoid contact with poultry products
coming from poultry that is not
slaughtered by the poultry industry.
Avian influenza is closely
connected to the poultry industry in
the public’s mind because AI can
spread via chickens that have come
in contact with the virus. This is
true not only in free range farming,
but also in backyard farming and
with fighting cocks. Therefore, it is
important to explain to the public that
they have to avoid all unnecessary
contact with poultry, wild fowl, and
domestic birds in order to prevent the
virus jumping to humans.
Lessons Learned
The Dutch poultry industry and
Dutch government learned a very
important lesson during the 2003
AI crisis in Europe. As a result,
all farms in the Netherlands are
inspected for AI once a year; all free
range farms are inspected four times
per year and during the migration
season, all free range poultry have
to be kept inside or under a net. The
costs for this operation were covered
by the farmers themselves. From this
crisis, several lessons can be learned
and applied to the poultry industry
in the U.S.
Lesson One: Be Prepared!
Why did the Dutch farmers accept
such a drastic measure and such
high costs? Because they had to
survive the financial consequences
of the first major outbreak in 2003.
Unprepared and neglecting their
own responsibility, they trusted the
government to take care of the crisis.
They felt that if a disaster struck,
the government would act and they
would not have to worry.
Now, after the experience of
2003, the farmers know better.
Now they know they have to play
an active role in surveillance and
biosecurity programs, but that
was not the case in 2003. At that
time, the farmers only thought in
terms of financial compensation
“The consequences
are clear. The public
links the outbreak of
Avian Influenza directly
to poultry, because
of the ban on poultry
products.”
lose and the best strategy to control
potential negative effects of AI is to
be open with the public. It is in the
best interests of the poultry industry
to launch a campaign to show that
the industry does everything it can
to prevent an outbreak and also that
the industry takes animal welfare
issues seriously.
Informing the Public
As the Dutch example shows, the
industry should take communication
about the consequences of avian
influenza seriously. They should
explain to the public and their
customers that it is perfectly safe to
eat poultry products as long as the
product is coming out of the grocery
store. People should not slaughter

6. 6
and relied on their assumption
that the government would take
care of them. After all, there were
funds created to cover the direct
costs: European Community (EC)
funds covered 50% of the direct
costs; local government covered
25%; and farmers’ funds (created
by the farmers organizations
themselves) covered 25%. What
the Dutch poultry industry learned
from the 2003 crisis is that it is far
more important to think in terms
of preparedness than in terms of
financial cost.
In 2003 the Dutch government
prepared for an AI outbreak based
on wrong assumptions. The Dutch
contingency plan in 2003 for an AI
outbreak was not successful because
it was based on an obsolete culling
method. The contingency plan
was still based on the use of HCN,
although another European Union
(EU) law forbids this type of nerve
gas. HCN is listed as a potential
weapon of mass destruction. The
services in charge ignored this fact
and the plan could not be carried
out. The fact that Holland was not
prepared with a well thought out
plan was the main reason for the
huge impact of the 2003 crisis. And
because of the great number of
affected farmers, the funds created
by the farmers’ organization dried
up the first week of the outbreak!
Take Holland as an Example
I don’t know exactly why, but
I am pretty well convinced that
unpreparedness is still too common
for most industries and governments.
False hopes and a reluctant
government are the best ingredients
for a future financial disaster. Here
are some facts and figures from
2003:
• In February 2003 the crisis
struck in Barneveld, the
heart of the Dutch poultry
industry. The R0 factor, the
reproduction factor, was 8.
That meant that one infected
farm was the source of
infection at 8 other farms.
• In total, 1,200 farms were
cleared and almost 32 million
birds were culled.
• Thirty-three percent of
all farms in Holland were
involved.
• The outbreak was stopped
within 10 weeks.
• On a 24/7 basis, more than
3,000 people were involved in
fighting the disease, culling
animals, and controlling the
operations.
• Total direct costs were
approximately 376 million
Euros; the uninsured indirect
costs were 1 billion Euros.
• 84 people were directly
infected with the virus and
they infected approximately
8,500 other people among
their families, friends, and
relatives.
There is a pattern that signals
things to come and we in Holland
started to understand this pattern:
• Migrating birds enter border
and mix with stationary birds,
most of the time in wetland
areas.
• Dead wild birds are found
and examined.
• Confirmation of avian
influenza.
These are the first signs,
signalling that procedures have to
be put in place to keep the virus
within the wildfowl population and
in a restricted area. The following
immediate actions have to be taken:
• Completely halt the transport
of birds and other animals.
• Control borders in the region.
• Ban fishing and hunting to
keep people out of the area as
much as possible.
• Rigorously cull all poultry in
the infected area, in an area
of about 1.5 miles around the
source of the outbreak.
• Daily sampling and
inspection.
• Reduce the number of people
entering the zone, especially
the press.
• Vaccinate against human flu
all farmers, veterinarians, and
poultry industry workers as
well as the general population
working or living within
the zone.
• Keep all domestic livestock
in barns.
• Prepare a ring vaccination
plan for poultry around the
infected zone.
Lesson Three: Protection Starts
with Proper Planning
This is the signal for the industry
to maximize efforts to protect
their farms, their employees, and
their families. This means that
each farm should work on an
individual contingency plan on a
“In 2003 the Dutch
government prepared for
an AI outbreak based on
wrong assumptions.”
• Unfortunately, 1 veterinarian
died.
• After one year, 25% of
the entire industry had not
survived.
As a note, Holland had to deal
with the lesser pathogen, H7N7
virus. If this had been the H5N1
version, the consequences would
have been much worse.
Lesson Two:Adequate Response
Looking at the facts above, it
seems that scientists are largely
concerned that governments as
well as the poultry industry are
not prepared for a crisis of this
magnitude.

7. 7
farm level, on a regional level, and
on a countrywide level. This will
help to keep a possible outbreak
within the industry as localized
as possible. The jump of the virus
itself into the industry can hardly
be prevented but, with a little luck,
these efforts will help to minimize
the consequences. Someone wisely
compared preparedness with ‘having
oil in your lamp when you know
darkness is coming.’
Lesson Four: Safety Before
Animal Welfare
One thing I have learned from
my experience in the field is that
safety of the operators has to be
maximized. New techniques are
needed to minimize the number of
operators needed and to guarantee
that animals are culled in the most
humane manner. This is a tough
job and not very rewarding, but
is absolutely vital to prevent a
pandemic through the operators. It is
quite simple. Technically speaking,
culling animals can never be done
in an animal welfare friendly way.
In spite of all efforts to choose the
best possible culling option, the
technique is only a small part of the
operation. It is largely in the hands
of those who carry it out and control
the culling operation. These people
include cullers, veterinarians, and
governmental officials in the field
who carry out the responsibility
for the operations. It is never the
scientists, animal welfare people,
or politicians who risk their lives
by going in the infected areas.
Animal welfare is a very important
responsibility, but stopping the
spread of the disease must always
be the highest priority. By stopping
the spread of the disease, the lives
of millions of animals can be saved.
However, in the aftermath of a
crisis, those who were responsible
for the culling operations are always
the first to be blamed for the killing
of innocent animals.
Lesson Five: Manage the Chain
When it comes to responsibility
to prevent an outbreak, a ‘hobby
farmer’ with a stock of five birds in
his backyard is just as responsible
as a broiler farmer with a stock of 1
million birds. The difference lies in
the details, but everything possible
has to be done to prevent the spread
of the virus.
Lesson Six:The Method of Choice
The most appropriate culling
method for the backyard farmer
may be totally different from that
of the commercial farmer. But for
all categories of farming, dedicated
methods have to be in place before a
possible outbreak. The best methods
are:
• Gas bags. An improvement
on this method is the
use of bags made out of
biodegradable plastic that are
put into dustbins. The bags
are first filled with at least
60% carbon dioxide before
being filled with animals. The
pre-filling renders the animals
unconscious before they die,
so they do not suffer. The
animals are stunned within 30
seconds and die within one
minute. The bags, together
with some manure, are then
landfilled above groundwater
level. After one year, the
bag is gone, together with
the birds and the virus. This
flexible and effective low cost
method is the preferred way
to cull small flocks (up to
1,000 birds).
• Container systems. There
are three types of containers
in use in Holland: small 340
litre bins, 1.100 litre wheelie
bins, and 20 foot container.
The most widely used size is

8. 8
the 1,100 litre container. All
systems work on the same
principle: first the containers
are filled up with a minimum
of 60% carbon dioxide before
the animals are put in. As with
the gas bags, the birds are
culled within 30 seconds and
killed within one minute. This
method is mostly used for
layer hens in cages, because
the animals have to be taken
out of their cages anyway.
• Electrocution. The fourth
method is the use of a
mobile electrocution line,
similar to what is used in
slaughterhouses, but with a
much higher electric current.
The birds are killed within
a fraction of a second and
therefore this is the preferred
method from an animal
welfare point of view. A
negative aspect of this method
is that the animals have to
hang upside down before they
are killed. This technique can
generally be used for all types
of animals including broilers,
layer hens, turkeys, geese, and
ducks. This technique is often
used if the fifth method, stable
gassing, failed.
• House gassing. Carbon
dioxide gas is pumped under
pressure into a house with
broilers, parent stock, and
young turkeys. This method
only works if the stable
can be sealed off, keeping
sufficient space for the air
in the stable to escape at the
moment the carbon dioxide
is pumped in. It takes 30
minutes to one hour until the
birds die. From an animal
welfare point of view, it is
better to choose a method that
leads to a quicker death, but
when the quantity of birds per
house is large, there are not
many alternatives. This is the
method of choice in Europe
for culling large quantities of
birds, especially broilers. It
is important to keep in mind
that in Holland, the house
gas method could only be
practiced when the house was
suitable for this method, as
was the case in 33% of Dutch
houses. That means that 67%
of all the houses in Holland
were not suitable candidates
for the use of the preferred
gassing method, due to the
type of housing or to the type
of animal (ducks, layer hens,
turkeys, very young birds).
So even though house gassing
was the preferred method,
67% of all the farms had to
use a variety of other culling
methods.
carcasses were put into air- and
watertight containers and transported
by truck to the rendering plant. The
maximum rendering capacity was
250 tons per day with a limited
number of vehicles to transport the
dead animals to the rendering plants.
Despite the risk that transporting
diseased birds could cause further
spread of the disease, there were
few other options available at that
time. Landfill in Holland is nearly
impossible, because we live below
sea level, so the risk of the virus
touching groundwater level was too
high and house fermentation had not
been developed at that time.
Conclusion: Start
Yesterday
It is important to go back to
common sense and stay with the
facts. There is no reason to panic
yet. However, only a few countries
have the necessary action plan to
control an outbreak in the first 24
hours after it is confirmed. At the
moment there are few specialists
working in this field worldwide who
sell or rent the culling equipment
described above.
As a specialist with experience
in this field, I am convinced that we
will be able to manage a large scale
outbreak within the poultry industry.
There is one condition: the industry
has to take this very seriously and
needs to take the responsibility and
act—starting yesterday.
Harm Kiezebrink is an independent
consultant who works for the poultry
industry, governments, and veterinary
services worldwide. In addition to the crises
in Holland and Belgium, Harm was involved
in control outbreak planning in other
European countries such as Spain, Portugal,
France, England and Germany, as well as in
Asia (China, Thailand and Vietnam). Harm
is currently active in Romania advising the
minister of agriculture and representatives of
the Romanian poultry industry.
• Carbon monoxide. Don’t use
carbon monoxide. In addition
to availability problems,
carbon monoxide is highly
flammable, and caused a fire
on at least one farm during
the Dutch outbreak.
In practice, a variety of different
methods must be in place before an
outbreak occurs.
Lesson Seven: Beware of
Unexpected Limitations
Whatever method is chosen,
success in culling always comes
down to the entire operation, rather
than the technique. The make or
break factor in Holland was disposal
of the dead birds. In Holland, the
method of choice was rendering
the animals. The rendering capacity
dictated the speed of operation. The
“It is important to go
back to common sense
and stay with the facts.
There is no reason to
panic yet.”

9. 9
Depopulation of Poultry Flocks during Disease Outbreaks
and Other Catastrophic Events
by Dr. Nathaniel L. Tablante
Depopulation of poultry flocks is
necessary during infectious disease
outbreaks and natural disasters. In
the case of avian influenza, which
has gained notoriety in recent years
because of the potential risk to
human health, destruction of infect-
ed flocks is required in order to
prevent further spread of the disease.
The destruction of these flocks must
be done as quickly as possible, using
proper and humane methods of mass
euthanasia.
The word euthanasia is derived
from two Greek words that mean
“good death.” The term essentially
refers to a humane death that occurs
with a minimum of fear, pain, and
distress. In 2000, the American
Veterinary Medical Association
(AVMA) developed specific
guidelines on the euthanasia of
animals. The 2000 Report of the
AVMA Panel on Euthanasia states
that “under unusual conditions
like disease outbreaks and natural
disasters that require depopulation,
the most appropriate technique that
minimizes human and animal health
concerns must be used.” According
to these guidelines, the method
of euthanasia must result in rapid
loss of consciousness, cardiac or
respiratory arrest, and ultimate loss
of brain function.
Choosing the method of
euthanasia depends on several
factors such as human safety, skill
of the operator, aesthetics, cost,
other limitations, and consideration
of the humaneness of the method.
Currently, only two methods of mass
euthanasia of poultry are considered
acceptable by the AVMA. These are
1) cervical dislocation, and 2) use
of inhalant gases such as carbon
dioxide (CO2). In a disease outbreak
where prompt response is critical,
cervical dislocation is impractical,
labor intensive, and time consuming
as it involves individual handling
of thousands of birds. Therefore,
inhalant gases like CO2 are widely
used to euthanize large numbers of
birds at a time. Carbon dioxide for
mass euthanasia of poultry, although
not perfect, is widely used because
it is inexpensive, readily available,
and poses minimal risk to humans.
To be effective, a concentration of
60 to 70 percent must be achieved.
Broiler chickens and turkeys are
sensitive to CO2 but waterfowl are
more resistant and require higher
concentrations and longer exposure
time.
For meat-type poultry, the
following methods of CO2
euthanasia have been developed and
used in actual AI outbreaks:
1. Whole house method.
• Used mainly in breeder
houses.
• Involves the use of a CO2
tanker truck.
2. Partial house method.
• Used also in breeder
houses.
• Involves driving birds into
one end of the house in
the litter area and sealing
the area off with a sheet of
poly.
• Utilizes CO2 tanker trucks
or 50 lb. cylinders.
3. Portable panels with tarp.
• Works best with turkeys.
• Involves the use of ply-
wood panels that are set up
against posts.
• Birds are driven into the
enclosure formed by the
panels.
• CO2 cylinders are placed
on the floor and a sheet of
poly is placed on top of the
birds using the top edge of
the panels for support.
4. Livehaul euthanasia cabinet.
• Ideal for broilers.
• Utilizes regular livehaul
crates.
• Fabricated steel cabinet is
placed on top of crate con-

10. 10
taining the birds.
• CO2 is pumped into the
cabinet.
5. Poly euthanasia tent.
• Ideal for broilers in clear
span houses.
• Birds are driven to one end
of the house one group at a
time.
• CO2 cylinders are placed
on the floor and poly is
placed on top of birds in
two opposite and overlap-
ping layers.
• Works well with in-house
composting of carcasses.
These methods were developed
and later refined by poultry industry
personnel during actual outbreaks of
avian influenza. Those involved in
depopulation of poultry flocks know
fully well that mass euthanasia of
poultry is not a pleasant task. It is
physically and emotionally stressful
for all personnel involved in the
process and distressful for poultry
as well if the euthanasia is done
improperly. However, in the event of
a catastrophic disease such as avian
influenza, it is a necessary evil. In
order to expedite the process, protect
the welfare of poultry, and ease the
physical and emotional burden on
humans, the following criteria must
be met:
1. All personnel involved in
depopulation of poultry
flocks must undergo intensive
training on emergency
preparedness, poultry welfare,
and methods of euthanasia,
and must follow the Centers
for Disease Control guidelines
for poultry workers involved
in avian influenza control.
(See http://www.cdc.gov/flu/
avian/professional/protect-
guid.htm for details.)
2. The poultry industry, along
with state and federal agency
representatives must prepare
in advance for an emergency
poultry disease outbreak
by having an action plan in
place, including provisions for
necessary personnel, supplies,
and equipment.
3. The different methods of
CO2 euthanasia must only be
performed under the direct
supervision of a veterinarian
or trained professional. This
professional must insure
that the birds are treated in
a humane manner from start
to finish. Acts of animal
cruelty like the use of baseball
bats and woodchippers are
absolutely forbidden and
those who commit such
inhumane acts will be
prosecuted accordingly.
4. A safety officer to monitor
compliance with OSHA
guidelines and ensure safe
levels of CO2 for humans
must always be present during
the euthanasia procedure.
Practicing the different methods
of mass euthanasia and carcass
disposal through simulated exercises
is strongly recommended. Not
having the necessary skills and
resources when an outbreak occurs
can result in the loss of valuable
time to control the outbreak, which
may result in a major economic
disaster and bad publicity. Extension
specialists and poultry professionals
must play a key role in educating
poultry workers, farmers, and all
those involved in disease control
and eradication efforts on proper
methods of euthanasia and carcass
disposal.
References:
American Veterinary Medical Association, 2000
Report of the AVMA Panel on Euthanasia, J
Am Vet Med Assoc 2001, 218:669-696.
UC Davis, Center for Animal Welfare, Euthanasia
of Poultry: Considerations for Producers,
Transporters, and Veterinarians (undated).
Disposal Options for Avian Influenza Flocks
by Bud Malone
Are you prepared to deal with
catastrophic mortality disposal due
to Avian Influenza (AI) on your
farms? Do you have disposal pro-
cedures, materials, knowledge and
approvals in hand that allow you to
respond to this kind of event in a
swift, biosecure, economical, envi-
ronmentally and socially acceptable
manner? There have been several
recent examples in which there was
uncertainty and lack of knowledge
on methods of mass disposal, lack
of preparation to deal with this type
of catastrophic event, and perhaps
more important, not having proce-
dures pre-approved by local and
state regulatory authorities. The
consequence of these situations has
been conflict, delays in responding
to the emergency at the most critical
time period, and added overall cost
to deal with the disease crisis.
The following are some of the
questions that need to be asked
when analyzing potential disposal
options for a disease outbreak.
What local, state, and/or federal
regulations apply to this situation?
What are the viable disposal options
given the situation on each farm and
house on that farm? Is the house
clear-span or pole? How many and
what size of birds are involved?
What resources, equipment and
disposal options are available on the
farm, from the poultry company or
agency(s) overseeing this matter?
Is the AI a low or high pathogenic

11. 11
form? With the recent media and
human health attention given to
“bird flu” (H5N1) in Asia and now
Europe, additional safeguards are
needed to insure public health. And
let’s not forget, how will the public
perceive the disposal option being
recommended?
The following are some brief
highlights of disposal options for
AI infected flocks used in the U.S.
Local, state and federal guidelines
will dictate which options are
appropriate given the nature of the
AI event.
Burial. At one time, on-farm
burial was the predominant
disposal option for many types of
catastrophic losses. This practice is
one of the simplest and most cost-
effective ways to deal with mass
mortality losses. Trenches with
carcasses placed 2-3 feet above the
seasonal high water table, placed
at a maximum of 4 feet thick and
covered with 2 feet of fill on top
of the birds has been used for
various types of mass mortality
losses. Although some states have
previously relaxed environmental
standards for burial when dealing
with an emergency, this situation is
changing due to increasing water
quality and public perception
concerns. In many Delmarva
locations having high seasonal water
tables, finding a suitable location
can be a major challenge. In a
disease emergency, trench burial
above the water table may be needed
but not the preferred method of
disposal of AI-infected flocks.
Sanitary Landfill. The use of
sanitary landfills has been used
for mass disposal of AI flocks
in the last few decades. Since all
landfills do not accept carcasses,
pre-approval is required and there
can be logistical challenges when
coordinating the transportation
and deposition of large volumes
of carcasses to these sites. Costs
associated with transportation and
tipping fees can be significant.
During several recent AI outbreaks,
there were indications that disposal
options that removed infected
carcasses from farms posed a
potential risk of spreading the virus
to other farms.
Incineration. Portable
incineration units (i.e., Air
Curtain™) have been used on a
limited scale in recent AI outbreaks.
Although the end product is
very biosecure, there are some
logistical and environmental
issues with this procedure. The
units need to be transported to
the region of the country having
the catastrophic losses. Carcasses
are then transported to a central
and preferably remote receiving
site. The incineration process is
somewhat slow, loading decomposed
carcasses poses a problem and it
will require disposal of 0.3 tons of
ash per ton of carcass. Without the
proper fuel source and supervision
of the process, smoke and odor
can create nuisance complaints.
Based on Virginia’s experience
with incineration during their 2002
outbreak, this disposal option will
likely be a low priority for any
future AI events.
Composting. There has
been increasing acceptance
of composting as a practical,
economical and environmentally
sound method for disposal of many
types of catastrophic mortality
events. Following a major heat
loss on the Delmarva Peninsula
in 1995, the local universities
conducted a demonstration and
developed guidelines (Carr et
al., 1996) for outside windrow
composting of catastrophic heat-
loss mortality events. In 2003
another demonstration was
conducted on Delmarva to evaluate
and demonstrate the windrow
composting procedure inside poultry
houses. A year later on Delmarva,
this procedure was implemented as
a means to contain and inactivate
the H7N2 AI virus in the carcasses
and litter on the three infected farms
(Malone et al., 2004). The procedure
used on these farms involved the
formation of a single windrow 10
to 12 feet wide by 3 to 5 feet high
down the center of the house. The
litter and carcasses were mixed
uniformly and capped with litter or
sawdust to cover exposed carcasses.
This procedure requires 0.8 inches
of litter/carbon per pound of carcass
per square foot floor space (Tablante
and Malone, 2005). Crushing
or shredding carcasses prior to
windrowing reduces the additional
carbon requirement to compost
large carcasses such as roasters and
turkeys (Bendfeldt et al., 2005).

12. After ~2 weeks the windrows can be
turned in the house, capped to cover
any exposed tissue, and allowed to
compost for another 10 days prior
to removal. An alternative procedure
is to remove the compost after
the first 2 weeks and place it in a
covered windrow outside the house.
Temperatures in the compost exceed
130º F, enough to inactive the virus
within a short period of time.
An Ag-Bag composting system
has been employed on a limited
scale during several recent AI events
in the U.S. and Canada. This system
requires specialized equipment
to mix carcasses with the carbon
source, load the mixture into the
bags and maintain proper aeration.
Due to logistical considerations,
it may be more appropriate to
transport the carcasses to a central
site for composting with this system.
Since broiler breeder and caged
layer farms may have limited on-
farm carbon sources and these
types of carcasses tend to be more
difficult to compost, transporting
these mortalities to a centralized and
professionally operated Ag-Bag site
may be appropriate.
In summary, when the decision
is made to depopulate a farm for
disease control purposes, selection
of the disposal method should focus
on minimizing disease spread.
Several recent AI events suggest
every effort should be made to
inactivate AI virus prior to carcass
(and litter) removal from the house.
There is growing consensus that
in-house composting is the most
biosecure disposal method for
a flock with a highly infectious
disease like avian influenza.
References
Bendfeldt, E., R. Peer, G. Flory, G. Evanylo, L.
Carr and G. Malone. 2005. Can Catastrophic
Turkey Mortalities be Composted In-House
as a Means of Disposal? Symposium on
Composting Mortalities and Slaughterhouse
Residuals. Portland, MA.
Carr, L., H. Brodie, J. Martin, Jr., G. Malone,
D. Palmer and N. Zimmermann. 1996.
“Composting Catastrophic Event Poultry
Mortalities.” University of Maryland Fact
Sheet No. 732.
Malone, G., S. Cloud, R. Alphin, L. Carr and N.
Tablante. 2004. Delmarva in-house carcass
composting experiences. Proceedings 39th
National Meeting on Poultry Health and
Processing. Ocean City, MD. pp. 27-29.
Tablante, N. and G. Malone. 2005. Guidelines for
In-House Composting of Poultry Mortalities
Due to Catastrophic Disease. Compact disk
available from Universities of Maryland and
Delaware.
MARYLAND COOPERATIVE EXTENSION
U.S. Department of Agriculture
University of Maryland, College Park
College Park, Maryland 20742
Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, University of Maryland, College Park, and local governments.
Cheng-i Wei, Director of Maryland Cooperative Extension, University of Maryland.
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