A new case of highly pathogenic avian influenza (HPAI) was confirmed in a commercial turkey flock in Chester County, Pennsylvania.

According to the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS), the case was confirmed on March 16 and involved 11,800 meat turkeys.

This is the first HPAI case in Chester County to be classified by APHIS as a commercial operation, although three previous cases were confirmed in the county from February 24 to March 4, and those cases collectively involved 15,000 birds APHIS described as WOAH (World Organisation for Animal Health) Poultry.

Pennsylvania has had more cases of HPAI in commercial flocks than any other state so far in 2023. All of the other cases confirmed this year were in Lancaster County.


In 2022, Pennsylvania ranked third in terms of commercial flocks affected by HPAI at 25. In terms of birds lost, Pennsylvania ranked fourth, with an estimated 4.35 million head of commercial poultry.

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 WATTPoultry.com. 

Read our ongoing coverage of the global avian influenza outbreak.