Cloacal swabs were collected from 300 broiler chicks (50 dead, 50 diseased and 200 healthy) for bacteriological examintion. Out of 300 examined cloacal swabs 26 (52%) dead, 28 (56%) diseased and 28 (14%) from healthy chicks were positive for bacteria. Moringa oleifera leaf extract inhibits growth of E. coli and Salmonella spp. Post bacteriological examination 120 chicks free from bacterial infection, one day old were divided into 3 equal groups. 1st group healthy chicks (control), 2nd and 3rd groups chicks received 200 mg/ kgm bwt watery and alcoholic moringa oleifera leaf extract daily for 30 successive days in drinking water respectively. Effect of moringa leaf extract on body weight, feed conversion rate and haemato-biochemical analysis beside pathological changes of some internal organ were study. Moringa leaf extracts (watery & alcoholic) induced significant increase in body weight gain, RBCs, Hb, PCV% WBCs, total proteins, albumin, globulins, SOD beside significant decrease in MDA and insignificant increase in AST, ALT, ALP but urea and creatinine insignificantly decreased and improved in feed conversion rate. Histopathological investigation revealed, Hepatic tissue, congestion and hyperplasia in bile duct epithelium. Renal tubules undergo interstitial aggregation of lymphocytes and regeneration. Intestine shows slight edema. spleen and bursa show hyperplasia of lymphocyte in white pulp. It could be concluded that Moringa leaf extract act antibacterial, growth promoter, antioxidant and have benefits effect in immunity and hemato-biochemical parameters.