Niigata prefectural officials were killing all the chickens at a farm in Sekikawa Village after about 40 were found dead there on Monday.
In the northern prefecture of Aomori, local authorities were destroying 16,500 ducks at a farm after some of them tested positive to the H5 bird flu strain in preliminary testing on Monday.
Authorities in Niigata and Aomori decided to restrict the movements of poultry and eggs within 3 kilometres of the farms in question.