Officials in protective suits head to a poultry farm for a suspected bird flu case in Higashikagawa, western Japan. (Reuters)

A fresh outbreak of bird flu has been found in the Japanese prefecture of Gunma, where 450,000 will be culled, according to the Japanese news agency Kyodo, using local administration data.

The disease was suspected on a farm near Maebashi, according to the news agency. A highly pathogenic strain of avian influenza was identified through genetic testing.

Authorities have apparently previously barred the transportation of hens and eggs within a 3-kilometer (1.8-mile) radius of the outbreak hot sites, as well as the export of chickens and eggs beyond a 10-kilometer radius.

The number of hens culled in Japan this season has already surpassed 10 million, marking a new high for Japan. In the previous season, from November 2020 to the end of March 2021, the poultry business suffered the most significant damage due to bird flu, with 9.87 million hens slaughtered and 52 outbreaks in 18 prefectures.

Experts attribute the outbreak to the fact that migrating birds arrived earlier than normal this year, and sickness spread quickly across regions. Bird flu has led the price of chicken eggs, which was already high due to inflation and surging food prices, to reach a 29-year high.