Arkansas, a major US chicken producer, has reported its first lethal avian flu outbreak in a year, amid an increase in cases across the country.

The outbreak is expected to increase export restrictions on U.S. poultry in major producing states, as buyers restrict purchases from infected areas.

The U.S. government reported a disease outbreak in Madison County, Arkansas, affecting 31,600 breeder pullets used for meat production.

Arkansas, the third-largest meat producer, experienced a chicken outbreak on a commercial farm in October 2022 in the same county.

Since 2022, avian flu has killed over 60 million birds in the U.S. and spread globally. The virus's prevalence increases during wild bird migrations, prompting the culling of infected poultry flocks to prevent its spread.

"We have taken immediate action to contain this disease," Arkansas Agriculture Secretary Wes Ward said.

Alabama, the second-largest U.S. chicken producer, has confirmed its first outbreak at a commercial farm, affecting 296,500 gamebirds. Mexico, the largest export market for U.S. chicken, has blocked poultry shipments from the infected county.

The U.S. in October confirmed its first case of avian flu on any commercial poultry farm since April in South Dakota. Minnesota, the biggest U.S. turkey producer, and Iowa reported fresh outbreaks as well.

The World Organization for Animal Health said on Thursday that Mexico reported its first outbreak this season on a farm, just a month after the country declared it was free of the disease.