Japanese health officials began culling of 150,000 chickens in the central region of Aichi, in order to curb the spread of bird flu outbreak.
Since November Japan has confirmed five cases of bird flu at farms in four of the country's 47 prefectures. Some 600,000 chickens have been culled.
The flu has also hit Kagoshima and Miyazaki prefectures on southwestern Kyushu island, which are major poultry farming areas.
In Miyazaki, a foot-and-mouth outbreak last year forced the slaughter of almost 300,000 farm animals.