A commercial egg laying flock in Weld County, Colorado, was infected with highly pathogenic avian influenza. The flock consisted of 1,928,000 hens.

According to the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS), the presence of HPAI was confirmed on June 7.

This case marks the third case of HPAI in a commercial poultry flock in Colorado in 2022, and the second in a commercial egg operation in the state. The virus was also confirmed in another Weld County layer flock on April 29, with that case involving 1,366,200 birds. HPAI was also confirmed in a commercial broiler breeder operation in Montrose County on April 19, with that case involving about 58,000 chickens.

Colorado has also had confirmed cases of HPAI in two backyard flocks and at one animal rescue and rehabilitation center.

Prior to the most recent Weld County case, the last time a commercial flock in the U.S. was affected by HPAI was June 2, when a commercial duck operation in Berks County, Pennsylvania was stricken. Berks County is also where the previously most recent case of HPAI in a commercial egg operation was confirmed. That case, which involved 79,000 hens, was confirmed on May 17.


With the latest HPAI case, the number of commercial birds affected by the virus in 2022 has reached 39,364,200.

So far in 2022, HPAI has been confirmed in commercial poultry in the states of Michigan, Wisconsin, Oklahoma, Minnesota, North Dakota, South Dakota, Nebraska, Kansas, Iowa, Missouri, Kentucky, Indiana, Colorado, North Carolina, Pennsylvania, Delaware, Maryland and Utah. The virus has also been found in commercial game bird operations in Texas, New York and South Dakota.

To learn more about HPAI cases in North American commercial poultry flocks, see an interactive map on WATTPoultry.com.

Read our ongoing coverage of the global avian influenza outbreak.