Highly Pathogenic Avian Influenza (HPAI)

Colorado State University Extension 

What is Avian Flu?

Avian influenza (AI) is caused by an influenza type A virus which can infect poultry (such as chickens, turkeys, pheasants, quail, domestic ducks, geese, and guinea fowl) and is carried by free flying waterfowl such as ducks, geese and shorebirds. AI viruses are classified by a combination of two groups of proteins: hemagglutinin or “H” proteins, of which there are 16 (H1–H16), and neuraminidase or “N” proteins, of which there are 9 (N1–N9). Many different combinations of “H” and “N” proteins are possible. Each combination is considered a different subtype and can be further broken down into different strains which circulate within flyways/geographic regions. AI viruses are further classified by their pathogenicity (low or high)—the ability of a particular virus strain to produce disease in domestic poultry.

La información en Espanol: Colorado Department of Agriculture.

Biosecurity Information

Biosecurity Basics

  • Keep visitors to a minimum. Only allow those people who take care of your poultry to come in contact with your birds, this includes family and friends. Keep track of everyone who is on your property at all times. Make sure everyone who has contact with your flock follows biosecurity principles.

  • Wash your hands before and after coming in contact with live poultry. In addition to potentially spreading disease from farm to farm or bird to bird, you can also spread germs such as Salmonella that can impact human health. Wash with soap and water (always your first choice). If using a hand sanitizer, first remove manure, feathers, and other materials from your hands because disinfectants will not penetrate organic matter or caked-on dirt.

  • Provide disposable boot covers (preferred) and/or disinfectant footbaths for anyone having contact with your flock. If using a footbath, be sure to remove all droppings, mud or debris from boots and shoes using a long-handled scrub brush BEFORE stepping into the disinfectant footbath, and always keep it clean. 

  • Change clothes before entering poultry areas and before exiting the property. 
    Visitors should wear protective outer garments or disposable coveralls, boots, and headgear when handling birds, and shower and/or change clothes when leaving the facility.  

  • Clean and disinfect tools or equipment before moving them to a new poultry facility. Before allowing service vehicles, trucks, tractors, or tools and equipment—including egg flats and cases that have come in contact with birds or their droppings—to exit the property, make sure they are cleaned and disinfected to prevent contaminated equipment from transporting disease. Do not move or reuse items that cannot be cleaned and disinfected—such as cardboard egg flats.

  • Look for signs of illness. Know the warning signs of infectious bird diseases.

  • Report sick birds. Don’t wait. If your birds are sick or dying, call a local veterinarian, cooperative extensive service, or state veterinarian. Call USDA toll-free at (866)-536-7593.

For more information about biosecurity practices, including checklists you can follow, visit the Defend the Flock Resource Center

Information is from the USDA Animal and Plant Health Inspection Service website.  For more information about biosecurity visit Defend the Flock.

Avian Flu Symptoms

Birds infected with the HPAI virus may show one or more of the following signs:

  • Sudden death without clinical signs;
  • Lack of energy and appetite;
  • Decreased egg production or soft-shelled or misshapen eggs;
  • Swelling of head, comb, eyelid, wattles, and hocks;
  • Purple discoloration of wattles, comb, and legs;
  • Nasal discharge, coughing, and sneezing;
  • Incoordination; or
  • Diarrhea

Information is from the USDA Animal and Plant Health Inspection Service website.  For more information please visit Defend the Flock - Signs of Illness.

Resources and Contacts

It is critical to report sick birds or unusual bird deaths.

Sick birds or birds that have died from unknown causes:

  • Call the Avian Health Hotline at Colorado State University (CSU):  (970) 297-4008 (may not be answered on nights/weekends)

Dead birds:

Multiple sick birds or multiple unusual bird deaths:

  • Call the Colorado State Veterinarian's Office (303) 869-9130 (veterinarian on call 24/7) or the USDA-Veterinary Services Colorado Office (303) 231-5385

USDA Healthy Bird Hotline:

  • Call the USDA Healthy Bird Hotline with questions at (866) 536-7593 (May not be answered on nights/weekends)

Wild birds:

  • If you find three or more dead birds in a specific area within a two week period OR if you see live birds showing clinical signs of disease, please contact your local Colorado Parks and Wildlife Office.

Additional Resources and Links

Colorado Department of Agriculture (CDA) Website on HPAI:

Additional Resources:

CSU Veterinary Diagnostic Laboratory- Avian Health - Our Avian Diagnostics section offers disease testing services and flock health support for the U.S. poultry industry including: Commercial poultry, Backyard flocks, Waterfowl flocks, Upland gamebird facilities and Pet birds.

USDA Defend the Flock - We talked extensively about this website on the webinar because it is an excellent resource for backyard flock biosecurity.

USDA HPAI Detections - Monitor the national outbreak situation in both backyard and wild bird populations.

Colorado Parks and Wildlife Local Offices - Report wild bird deaths.

Mental Health Resources:
Lastly, we understand how important your poultry flocks are to you and we truly appreciate you taking the time to help us help you.  If you or anyone you know may be dealing with stress, fear or overwhelming concerns about HPAI and would like to speak to a mental health professional, help is available.  Colorado Crisis Services (844) 493-8255 or text “TALK” to 3825.

Latest Update

For the latest update, please visit Colorado Department of Agriculture.


April 17, 2022

A flock in La Plata County was detected.  The flock was experiencing significant illness and was humanely euthanized on April 17, 2022 and disposed of by burial on site. The premises is under a 150 day quarantine. A 10k Control Area was established and surveillance teams were deployed to identify additional poultry in the area. Education was provided to poultry owners for active observational surveillance.


April 15, 2022

On April 15, 2022, the State Veterinarian’s office was notified of a mortality event at a commercial broiler breeder facility in Montrose County.  Samples from the flock, known as Montrose01, were submitted to the Colorado State University Veterinary Diagnostic Laboratory for preliminary testing, with confirmation of HPAI made by NVSL on April 19, 2022. The 60,000 bird flock is being euthanized to control the spread of the virus.

The State Veterinarian has issued a Quarantine Order in parts of Montrose and Delta Counties to limit movement of birds in and out of the area. Commercial and backyard poultry operations within the Quarantine Area are required to halt any movement of poultry and poultry products, as defined in the order, in and out of the area.


April 9, 2022

Contacts: APHISpress@usda.gov

WASHINGTON, April 9, 2022 – The United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed the presence of highly pathogenic avian influenza (HPAI) in a non-commercial backyard flock (poultry) in Pitkin County, Colorado.

Samples from the flock were tested at the Colorado State University Veterinary Diagnostic Laboratory, part of the National Animal Health Laboratory Network, and confirmed at the APHIS National Veterinary Services Laboratories in Ames, Iowa.

APHIS is working closely with state animal health officials in the state on a joint incident response. State officials quarantined the affected premises, and birds on the property will be depopulated to prevent the spread of the disease. Birds from the flock will not enter the food system.

According to the U.S. Centers for Disease Control and Prevention, the recent HPAI detections do not present an immediate public health concern. No human cases of these avian influenza viruses have been detected in the United States. As a reminder, the proper handling and cooking of all poultry and eggs to an internal temperature of 165 ˚F is recommended as a general food safety precaution.

As part of existing avian influenza response plans, Federal and State partners are working jointly on additional surveillance and testing in areas around the affected flocks. The United States has the strongest AI surveillance program in the world, and USDA is working with its partners to actively look for the disease in commercial poultry operations, live bird markets and in migratory wild bird populations.

Anyone involved with poultry production from the small backyard to the large commercial producer should review their biosecurity activities to assure the health of their birds. APHIS has materials about biosecurity, including videos, checklists, and a toolkit available at Defend the Flock Resource Center.

USDA will report these findings to the World Organisation for Animal Health (OIE) as well as international trading partners. USDA also continues to communicate with trading partners to encourage adherence to OIE standards and minimize trade impacts. OIE trade guidelines call on countries to base trade restrictions on sound science and, whenever possible, limit restrictions to those animals and animal products within a defined region that pose a risk of spreading disease of concern.OIE trade guidelines also call on member countries to not impose bans on the international trade of poultry commodities in response to notifications in non-poultry.

APHIS will continue to announce the first case of HPAI in commercial and backyard flocks detected in a State but will not announce subsequent detections in the State. All cases in commercial and backyard flocks will be listed on the APHIS website at Detections of Highly Pathogenic Avian Influenza.

In addition to practicing good biosecurity, all bird owners should prevent contact between their birds and wild birds and report sick birds or unusual bird deaths to State/Federal officials, either through their state veterinarian or through APHIS’ toll-free number at (866) 536-7593. APHIS urges producers to consider bringing birds indoors when possible to further prevent exposures. The Animal Health Protection Act authorizes APHIS to provide indemnity payments to producers for birds and eggs that must be depopulated during a disease response. APHIS also provides compensation for disposal activities and virus elimination activities. Additional information on biosecurity for backyard flocks can be found at Defend the Flock Program.

Additional background
Avian influenza (AI) is caused by an influenza type A virus which can infect poultry (such as chickens, turkeys, pheasants, quail, domestic ducks, geese, and guinea fowl) and is carried by free flying waterfowl such as ducks, geese and shorebirds. AI viruses are classified by a combination of two groups of proteins: hemagglutinin or “H” proteins, of which there are 16 (H1–H16), and neuraminidase or “N” proteins, of which there are 9 (N1–N9). Many different combinations of “H” and “N” proteins are possible. Each combination is considered a different subtype and can be further broken down into different strains which circulate within flyways/geographic regions. AI viruses are further classified by their pathogenicity (low or high)—the ability of a particular virus strain to produce disease in domestic poultry.


April 7, 2022

At the time of this email, HPAI has been detected in commercial or backyard flocks in 25 states. Colorado has seen wild bird detections in 4 counties (Denver, Morgan, El Paso, Sedgwick) and USDA Wildlife Services has increased HPAI surveillance in the wild bird population throughout Colorado.

Our primary goal right now is prevention -increase measures to keep HPAI out of our domestic poultry in the state. At the same time, we are quickly working on increasing our preparedness in the event we do have a detection in the state. We are asking everyone to:

  • Increase Biosecurity
  • Monitor flocks for signs of illness and production parameters
  • Report any suspicious disease events

Biosecurity is critical and our office is more than happy to assist with any biosecurity inquiries. Please reach out if we can be of any assistance.
Contact Information:

  • State Veterinarian’s Office - (303) 869-9130 (veterinarian on call 24/7)
  • CSU Avian Health Team - (970) 297-4008 (may not be answered on nights/weekends)
  • USDA Healthy Bird Hotline - (866) 536-7593 (may not be answered on nights/weekends)

You can find more details and information in the HPAI Post Webinar Document(PDF, 2MB).  There is great information with phone numbers, links to helpful websites and a link to a recorded webinar.


March 31, 2022

After the US Department of Agriculture confirmed detection of Highly Pathogenic Avian Influenza (HPAI) in wild birds in Sedgwick County last week, Colorado’s State Veterinarian advised issuing an emergency rule suspending all poultry shows, including meets, sales, swaps, and competitions. The state’s Agricultural Commission approved this emergency rule on March 30. The rule takes effect immediately and will last for 90 days, unless renewed or ended at an earlier date by vote of the Ag Commission and a recommendation of the State Veterinarian.

Questions and Answers and Fact Sheets

We understand that this is a challenging time and you may have a lot of questions.  Colorado State University has put a five page document together with lots of questions and answers with great information.

Please view the HPAI for Backyard and Exhibition Poultry Producers Q and A Report(PDF, 129KB).  In this report there are links to helpful websites and much more.

Colorado State University Veterinary Diagnostic Laboratories has put a wonderful Highly Pathogenic Avian Influenza Fact Sheet(PDF, 308KB) together.  Please view the great information.

Colorado State University Extension has created an educational flyer about Highly Pathogenic Avian Influenza(PDF, 700KB).  Please view the great information. 

Colorado Department of Public Health and Environment has wonderful information about what to do if you come across dead birds.  View the great information about Highly Pathogenic Avian Influenza(PDF, 138KB).


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