Tokyo/Hong Kong(CNN) 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 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.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."