State officials are confirming a suspected outbreak of avian flu among chickens at a large commercial egg farm in Weld County, with the governor’s office declaring a disaster after a year of relative quiet with the deadly and highly contagious bird disease.
Under state orders, Colorado commercial egg farms have had to kill millions of chickens at a time to head off avian flu outbreaks spreading to other farms and wild bird populations.
Lt. Gov. Dianne Primavera, acting as governor with Gov. Jared Polis in Washington, D.C., issued a verbal disaster declaration for the Weld County outbreak. Colorado Agriculture Department officials said Friday that Colorado State University had confirmed the new outbreak, but that the state waits for lab confirmation from another source at U.S. Department of Agriculture facilities in Iowa.
“We’re working with a producer, getting ready for a response, but we will not do anything until we get that (national) confirmation, which we’re expecting later today,” said Colorado Agriculture Department spokesperson Olga Robak, in an interview.
A disaster declaration “enables state agencies to continue to properly coordinate for mitigation of disease spread, response, consequence management, and recovery efforts,” the governor’s office said. Polis is negotiating Colorado River rights and drought response with other state and national officials.
It’s the first commercial farm outbreak of avian flu detected since mid-2024, Robak said. Last year “was a pretty slow detection year. But here in 2026, this is the fourth one,” Robak said. Three of those have been backyard bird detections. After Colorado egg and poultry farms killed millions of chickens to contain outbreaks earlier in the 2020s, the state’s agriculture sector also suffered the nation’s worst crossover of avian flu into dairy herds. In July of 2024, Colorado had identified 26 herds with cases of avian influenza.
Since 2024’s outbreaks, Colorado officials have monitored poultry and dairy workers carefully for any potential human crossover of avian flu, though it’s extremely rare. A few workers did test positive in 2024. They were responding to an outbreak of bird flu at a commercial egg-laying operation in Weld County, where nearly 1.8 million chickens were being culled following the virus’s discovery.
None of the workers required hospitalization. Their symptoms ranged from pink eye to what the state described in a news release as “common respiratory infection symptoms.”