Seroprevalensi dan Faktor Risiko Penularan Mycoplasma gallisepticum pada Peternakan Ayam Petelur Komersial di Kabupaten Blitar (SEROPREVALENCE AND( RISK FACTORS OF MYCOPLASMA GALLISEPTICUM INFECTION IN COMMERCIAL LAYER FARM IN BLITAR DISTRICT) - Diyantoro, Diyantoro (Faculty of Veterinary Medicine, Udayana University and Published in collaboration with the Indonesia Veterinarian Association, 2017)