New backyard avian influenza case confirmed in Colorado

New backyard avian influenza case confirmed in Colorado

The following message was distributed by the Colorado State Veterinarian’s Office on October 18, 2023.

The US Department of Agriculture’s (USDA) National Veterinary Services Laboratory (NVSL) confirmed a new case of Highly Pathogenic Avian Influenza in a backyard flock in Weld County, Colorado. The flock experienced a high mortality event, losing 20 of 24 chickens in the flock, after exposure to sick and dying wild geese on the premises. The remaining birds in the flock were euthanized.

“We had a much-needed reprieve of HPAI detections in the country from this spring to summer. Unfortunately, as we see the fall movement of migratory birds through the United States, including Colorado, we are beginning to see HPAI cases increase again,” said Colorado State Veterinarian Dr. Maggie Baldwin. “We will continue to work with commercial poultry and egg producers as well as backyard flock owners to ensure they adhere to strict biosecurity practices that can help keep birds safe and decrease the spread of the virus.”

Since April 2022, Colorado has experienced the largest foreign animal disease outbreak in state’s history with the loss of more than 6.2 million domestic poultry due to HPAI. CDA continues to update the HPAI Response page with current information (

The USDA’s Defend the Flock program has resources for bird owners, including sample biosecurity plans, videos, and tips on how to keep a healthy flock.

Additionally, the Colorado Department of Agriculture has tips on biosecurity, informational webinars, a form to report any sick birds, and more information about HPAI on the Avian Influenza page at

What bird owners can do:

INCREASE BIOSECURITY: Poultry owners must immediately increase biosecurity measures to protect their birds from HPAI. The USDA Defend the Flock website has helpful resources for keeping poultry healthy in any operation. Commercial poultry producers can use this toolkit to assess their biosecurity practices and preparedness.

MONITOR: Monitor your flock for clinical signs of HPAI, including monitoring production parameters (feed and water consumption, egg production) and increased illness and death.  Any changes in production parameters that could indicate HPAI should be reported.

REPORT: Veterinarians and producers must report any suspicious disease events in poultry flocks to the State Veterinarian’s office at 303-869-9130. If it is after hours, the voicemail message will indicate which veterinarian is on call.

If you have sick birds or birds that have died from unknown causes, help is available at the Colorado Avian Health Call Line at CSU, 970-297-4008.  

Wild birds: If you find three or more dead wild 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 information and resources: