Support WBURWhat we know about the deadliest U.S. bird flu outbreak in historyPlay04:11Download AudioBill ChappellDecember 02, 2022 ShareRescued chickens gather in an aviary at Farm Sanctuary's Southern California Sanctuary on Oct. 5 in Acton, Calif. A wave of the highly pathogenic H5N1 avian flu has entered Southern California, driven by wild bird migration. (Getty Images)
