Officials said the positive samples were found in a 50,000-bird layer chicken flock on a commercial poultry farm in Lehigh County.

Worries about the bird flu have prompted ZooAmerica in Hershey to make some changes. It's temporarily relocating its bird population to avoid contact with wild birds that may be infected with highly pathogenic avian influenza (HPAI).

As the bird flu continues to spread in the U.S., Massachusetts farmers must protect their flocks. But due to the recent rise in the disease, growing and raising their own food on property is a tradition that may have to be put on hold.

Lithuania has reported an outbreak of highly pathogenic H5N1 avian influenza, commonly called bird flu, on a laying hen farm in the western part of the country, the World Organisation for Animal Health (WOAH) said on Wednesday.