The Iowa Department of Agriculture says an egg-laying farm with 238,000 chickens brings the total number of infected farms to 50 in the state.
The farm is in Sioux County, which now has 11 cases of bird flu. Once the disease is confirmed by a U.S. Department of Agriculture laboratory in Ames, all the chickens will be euthanized.
Iowa has bird flu cases in 13 counties. Nearly 25 million chickens and 970,000 turkeys will die.
Minnesota, where 4 million turkeys have been affected by the flu, reported no new cases Wednesday.
The USDA reports more than 150 confirmed cases nationwide which will lead to the death of more than 32 million birds.