Pennsylvania’s first case of highly pathogenic avian influenza in a commercial flock was confirmed on February 1.

According to information from the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS), a commercial meat duck flock in Lancaster County tested positive for the virus. There were 32,000 birds in the flock.

On the same day, according to APHIS, the presence of HPAI was confirmed in another poultry flock of 3,200 birds in Lancaster County. However, that flock was not identified as part of a commercial operation.

Few states have been hit by HPAI as hard as Pennsylvania. In 2022, it lost 25 commercial poultry flocks and about 4.35 million head of commercial poultry. Nationwide, it ranked as the state with the third most flock losses and the fourth most bird losses.

Of those 25 flocks affected by HPAI in 2022, eight were in Lancaster County.


The re-emergence of HPAI in Pennsylvania poultry flocks comes just several weeks after Pennsylvania State Veterinarian Kevin Brightbill wrote a letter to poultry producers in the state, urging them to keep all Pennsylvania poultry indoors to prevent the spread of HPAI.

Other states to have confirmed cases of HPAI in commercial flocks in 2023 include 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.