U.S. avian flu outbreak worst in history (NASDAQ:IDXX) Seeking AlphaAvian flu outbreak wipes out 50M US birds, a record KSL.comAvian Flu Kills 50.54 Million U.S. Birds: Worst Outbreak in History PEOPLEAvian flu wipes out a record 50.5 million birds Washington ExaminerAvian Flu Kills Record 50.54M Birds in US Newsmax