A flock of 200,000 hens in Wisconsin is the first commercial U.S. chicken operation to become infected with a lethal strain of bird flu, the U.S. Department of Agriculture said, widening the impact of a virus that has killed hundreds of thousands of turkeys this year. The chickens were at an egg-laying facility in Jefferson County, Wisconsin, between Madison and Milwaukee, and represented the state's first case of the H5N2 flu, according to the Agriculture Department.