Japan has culled just under 10 million birds as it confronts a massive outbreak of avian flu, which is threatening to put further strain on poultry supply and increase the price of eggs. In a statement Tuesday, the agriculture ministry said 9.98 million animals had been killed this season, surpassing a previous record of 9.87 million that were slaughtered in fiscal 2020, during a previous bird flu crisis. The latest cull included mostly chickens, as well as small numbers of ducks and ostriches, a ministry official told CNN on Wednesday. The National Federation of Agricultural Cooperative Associations, known as Zen-Noh, gave a higher tally, saying approximately 10.9 million birds had been killed as of Tuesday night. “The supply of chicken eggs is expected to decrease due to the recent outbreak,” Zen-Noh, which is part of a national farm industry group, told CNN. “The market price is expected to soar.” The spread of bird flu has already pushed up egg costs around the world in recent months. In the United States, egg prices far surpassed the increase in other grocery items in the year through November, as the virus whittled down poultry flocks there. This year, US egg supplies will “remain constrained” through the first quarter, though flocks are expected to start repopulating faster as bird flu risks are contained, according to a 2023 outlook report by Rabobank. In Japan, wholesale prices for eggs reached a record high last month as shipments dropped, according to public broadcaster NHK. Higher feed costs for hens and the avian flu are worsening the outlook, it reported, citing comments from the agriculture ministry. Avian flu is caused by infections that occur naturally among wild aquatic birds, according to the Centers for Disease Control and Prevention. Infected birds can transmit the virus to other animals through their saliva and other bodily discharges. In Japan, the situation may not improve anytime soon as circulation of the virus has reached an all-time high. On Tuesday, the agriculture ministry said it had confirmed a new case of the disease at a farm in Hiroshima prefecture, housing about 835,000 hens. That took the number of overall outbreaks across the country to 58, surpassing the record 52 logged during the 2020 season. At least 23 Japanese prefectures are now affected by the issue, up from 18 in 2020, which was the previous all-time high, according to the ministry.