The lethal bird flu sweeping Minnesota turkey farms has touched down for the first time at a major chicken farm, an egg-laying operation in Wisconsin.

It is the first time that Wisconsin has been hit with the virus.

Also, Hormel Foods Corp. has acknowledged that highly pathogenic H5N2 flu has affected three more of its Minnesota turkey supply sites, bringing the total to seven. Minnesota is the nation's largest turkey producer, and the state's turkey growers association has put a dollar value on all flu-related turkey losses so far at $15.7 million.

Federal and Wisconsin regulators confirmed Monday the bird flu's presence in a flock of 200,000 chickens at a farm in Jefferson County, between Madison and Milwaukee in southeastern Wisconsin. In February, another strain of bird flu, H5N8, hit a California commercial chicken and duck farm with 114,000 birds.

The deadly H5N2 virus has been particularly hard on turkeys since it broke out earlier this year in the U.S. But chickens are susceptible, too, and the Upper Midwest has many commercial egg-laying farms.

Iowa is the nation's largest egg producer, while Minnesota is seventh, according to the American Egg Board, a trade group.

The bird flu is believed to be spread by waterfowl that carry the virus but don't get sick from it. The Wisconsin hen farm hit by the flu is in the same Mississippi flyway — a path for migrating ducks — that covers Minnesota.

So far, 14 Minnesota turkey farms have been hit by the bird flu, leading to the destruction of 900,000 birds. Half of those 14 Minnesota farms are tied to Hormel, owner of the well-known Jennie-O turkey brand.

Farms in Lyon and Cottonwood counties — both announced on Friday to have been struck by the flu — are independent farms that supply birds to Hormel. A contract farm raises company-owned turkeys and uses company-owned feed. A stricken farm in Watonwan County, also revealed Friday, is directly owned by Hormel.

One other Hormel-owned farm, a massive operation with 310,000 birds in Meeker County, also has been devastated by H5N2. Hormel relies on Minnesota and Wisconsin for its turkeys. Still, the number of birds killed makes up only a small percentage of Jennie-O's production, the company says on its website.

Minnesota annually produces about 46 million turkeys.

The H5N2 bird flu has also been reported in three commercial turkey flocks in South Dakota and one in North Dakota.

Nobody has gotten sick from the bird flu as it has spread through the United States over the past five months. Health officials say the virus does not pose a food safety risk; affected birds are killed and don't enter the food system.