Ohio leads the nation in recent bird flu cases among commercial poultry operations, with more than 4.1 million chickens and turkeys affected so far this year.

The first case of bird flu on a farm in Pennsylvania in 2025 was detected on a poultry farm in Lehigh County on Monday, the state's Department of Agriculture announced.

Both H9N2 and H5N1 were detected at the duck farm in Merced County, according to tests conducted by the US Department of Agriculture (USDA) National Veterinary Services Laboratory. The event began on November 23, with clinical signs that included increased deaths in the ducks.

A new strain of a highly pathogenic and rare strain of bird flu has been reported on a duck farm in central California.

A new strain of H5N9 bird flu was detected at a commercial duck operation in California's Merced County. All the ducks were euthanized.