Chickens at a farm in Ogawa, Ibaraki Prefecture, have tested positive for an antibody which indicates they were infected with a bird flue virus of the H5 strain in the past, the prefectural government said Saturday.

The Ogawa farm GP Center of Aikeien Co. Ltd is in Nakanobu district, Ogawamchi town, Higashi Ibaraki county, Ibaraki Prefecture.

The prefectural government imposed a ban on transferring chickens and eggs from within a 5-kilometer radius from the farm to places outside of the area. The farm will cull its approximately 90,000 chickens.