ANIMAL AND PLANT HEALTH INSPECTION SERVICE

Highly pathogenic avian influenza (HPAI) is a very contagious and deadly disease 

for poultry. All it takes is one infected bird, and the disease can spread from 

flock to flock within a matter of days. As with any highly contagious animal 

disease, a quick and early response is our best chance to limit the size and 

scope of the outbreak. Depopulating affected animals is a key part of the 

response: it’s one of the most effective ways to stop disease spread and protect 

U.S. animal health as a whole. 

Federal law gives the U.S. Department of Agriculture (USDA) authority to 

depopulate animals in these situations to stop disease spread. USDA’s goal is to 

complete this work within 24 hours of first detecting HPAI at a property. The 

sooner we act, the faster we can contain the outbreak and help business return 

to normal. 

Your case manager will walk you through the process as we prepare to 

depopulate your flock and find out—as best we can—how HPAI may have 

entered your facility and if it has spread to any neighboring farms. We will also 

handle the disposal process, working with you to make sure it’s done safely, in 

compliance with all applicable laws, and without spreading HPAI further.

Depopulation Methods

There are two main methods we use to depopulate HPAI-affected flocks: 

water-based foam for floor-raised birds and carbon dioxide gas for caged birds. 

These are the most humane and effective options available in an emergency 

situation involving mass numbers of birds. Trained personnel will arrive 

onsite and handle these tasks under the supervision of Federal and State 

animal health officials.

If our preferred methods don’t allow us to depopulate the flock as quickly as 

needed—within 24 hours—we must consider other options. These may include 

shutting off the facility’s ventilation fans (“ventilation shutdown”). Federal and 

State officials will carefully evaluate your farm and work with you to figure out 

the best option for meeting the goal of 24-hour depopulation. 

In every case, we take the decision very seriously and weigh many factors when 

choosing what depopulation method to use. These include, among other things, 

the size and type of the animals, their behavior, and their containment/housing 

facilities. We also look at the number of animals in the flock, the location of the 

farm and environmental conditions there, disease information, and available 

resources and personnel. 

Depopulation and Disposal

for Birds in Your HPAI-Infected Flock

There is a difference between 

“depopulation” and “euthanasia.”

Depopulation is when large 

numbers of animals must be 

destroyed in response to an animal 

health emergency. With depopulation, 

the welfare of the animals is given 

as much consideration as practical, 

but the situation is understood 

to be extenuating.

Euthanasia, however, involves 

transitioning an animal to death as 

painlessly and stress-free as possible. 

While euthanasia is preferable to 

depopulation, it is not always possible 

during an animal health emergency 

because of the need to move quickly 

to slow or stop disease spread.

During an HPAI outbreak, depopulating 

flocks within 24 hours is crucial. It’s the 

best way to eliminate the disease and, 

overall, is a more humane approach. 

A lengthier depopulation process can 

lead to a greater number of birds 

suffering the terrible effects of HPAI.

WHAT IS DEPOPULATION?
ANIMAL AND PLANT HEALTH INSPECTION SERVICE

USDA follows the recommendations of the American Veterinary Medical 

Association and the World Organization for Animal Health whenever possible. 

We use trained veterinarians, animal health technicians, and specialized 

contractors to complete depopulation work. Throughout the process, our 

focus is on keeping personnel safe while minimizing stress to the animals. 

Disposal Options

There are many safe methods for carcass disposal. These include composting, 

onsite burial, incineration, rendering, and landfilling. Each disposal option can 

take a different amount of time to complete. When deciding which method to 

use, we look at several factors, including the size of the flock, space 

requirements, associated costs, local conditions, and applicable laws. 

We also consider the benefits and limits to using each method:

• Composting. Contains the virus to the farm and produces a soil 

amendment/fertilizer product. However, composting requires ample flat 

space and may not be possible for all farming operations, such as egg layer 

facilities or other places where space is limited.

• Burial. Must be approved by the State environmental regulatory agency and 

may not be permitted if the water table is close to the ground surface.

• Incineration. A safe method for disposing of carcasses, but the fuel 

requirements are substantial and can be costly.

• Rendering. This involves processing carcasses until they are reduced to 

water, fat or tallow, and meat or bone meal. It is very effective but requires 

added safety precautions to make sure the virus does not become 

aerosolized and dispersed throughout the rendering plant. It is also 

disruptive for the plant’s normal operations.

• Landfilling. Landfilling allows safe and efficient disposal of large quantities 

of carcasses. However, individual landfill managers may put restrictions on 

the type or quantity of materials they accept.

Depending on the situation, we may end up taking a combined approach and 

use a few or all of these methods.

For More Information

If you have specific questions, talk with your case manager or call the nearest 

USDA office (www.aphis.usda.gov/animal-health/state-offices). 

For general information on HPAI and emergency response, go to 

www.usda.gov/avian_influenza.html and www.aphis.usda.gov/fadprep.

Here, you can also download USDA’s “Ventilation Shutdown Evidence & 

Policy,” which gives more technical details about this topic.

USDA is an equal opportunity provider, employer, and lender.

APHIS 91-85-010

Issued January 2016

ACTIONS YOU NEED TO TAKE

• Talk with your case manager about 

how you’ll be involved and if you’ll 

work directly with emergency 

responders on these activities.

• Wear personal protective 

equipment if you are on the farm at 

the time depopulation or disposal 

work is happening or if you are 

directly involved in this work. 

• Require that your employees also 

wear personal protective 

equipment if they are on the farm 

or helping with response activities. 

Your case manager can provide 

guidance on personal protective 

equipment if needed.

• Adhere to strict biosecurity 

procedures at your farm.

• Follow all other steps outlined by 

the response team to minimize risk 

of spreading the disease during 

the process. 

USDA’s goal is to complete 

depopulation work within 24 

hours of first detecting HPAI at a 

property. The sooner we act, the 

faster we can contain the 

outbreak and help business 

return to normal.