Three cases of highly pathogenic avian influenza (HPAI) were confirmed in commercial poultry flocks in Pennsylvania on March 4.

According to the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS), all three of those cases were confirmed in Lancaster County. Two of those cases involved commercial meat turkey flocks, while the other involved a flock of commercial duck breeders.

One of the turkey flocks involved approximately 25,000 birds, while the other involved approximately 20,000 birds. The duck breeder flock involved about 6,500 birds.

Pennsylvania had two previous cases of HPAI in commercial poultry flocks in 2023. One involved a flock of 97,700 commercial broilers and the other a flock of 32,800 commercial meat ducks. Both of those cases were also in Lancaster County.

In 2022, Pennsylvania lost 25 commercial poultry flocks to HPAI, more than all other states except for Minnesota and South Dakota. In terms of bird losses, approximately 4.35 head of commercial poultry died as a result of the HPAI outbreak. Only Iowa, Nebraska and Colorado lost more birds that year.


Eight of those flocks affected by HPAI in 2022 were in Lancaster County, involving commercial table egg layers, commercial meat ducks, commercial broilers and commercial broiler breeder pullets. Two of those layer flocks involved more than one million chickens.

In addition to Pennsylvania, other states to have confirmed cases of HPAI in commercial operations in 2023 include Illinois, Mississippi, California, Iowa, Virginia, Tennessee and Kansas.

To learn more about HPAI cases in commercial poultry flocks in the United States and Canada, see an interactive map on 

Read our ongoing coverage of the global avian influenza outbreak.