Highly pathogenic avian influenza has been confirmed in a backyard flock on a farm in Cornwall, just days after the government raised the bird flu risk level.

The first outbreak of bird flu in nearly a year has been confirmed at a biological poultry farm in Gelderland. An estimated 23,000 laying hens will have to be destroyed after the disease was detected at a farm in Putten.

Poultry on a commercial farm in England have been infected with the bird flu virus, the U.K. government said Sunday. The H5N1 virus was found in kept birds in St. Ives, a seaside town in Cornwall. All the poultry in the infected area will be humanely culled,