i MOLECULAR EPIDEMIOLOGY, RISK FACTORS AND ASSESSMENT OF ANTIBIOTIC RESISTANCE OF SALMONELLAE IN COMMERCIAL LAYER FARMS IN SIX SELECTED STATES IN NIGERIA BY IDOWU OLUWABUNMI FAGBAMILA DEPARTMENT OF VETERINARY PUBLIC HEALTH AND PREVENTIVE MEDICINE, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA AUGUST, 2016