The highly infectious H5N1 strain has caused outbreaks across the country. Now, Long Island’s last duck farm must kill its entire flock and may go out of business, its owner said.

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

The government is investigating a rare strain of avian flu, H5N9, detected on a duck farm in central California, according to the World Organisation for Animal Health. It marks the first reported outbreak of this strain in U.