Iowa reports more 'probable' bird flu cases

CHICAGO (Reuters) - Bird flu has been identified at five new sites in Iowa, including a commercial egg-laying operation in Buena Vista County that houses an estimated 5.5 million birds, the Iowa Department of Agriculture and Land Stewardship said on Thursday.

If highly pathogenic avian influenza is confirmed at the egg-laying site by the U.S. Department of Agriculture, the total number of U.S. cases would surpass 20 million birds, the most in U.S. history.

(Reporting by Julie Ingwersen; Editing by Jonathan Oatis)