The incidence of disease and damage will increase, if environmental control and acceptable management practices are not provided during the rearing period. Ascites affect young broilers with rapid growth, and the most critical factor in causing ascites syndrome is the lack of oxygen in body tissues (hypoxia). This research aimed to investigate the effect of olive leaves hydroalcoholic extract and probiotics (LactoFeed) on experimental ascites caused by levothyroxine in male broiler chickens. The present study was an interventional type, and for its implementation, a single-factor design was used in eight groups with 3 replicates. Data were analyzed based on a one-way analysis of variance. Blood parameters of male chickens were measured after 42 days. Biochemical factors of the blood serum of broilers included AST, ALT, ALT, TSHT, T4, T3, Glucose, Cholesterol, Triglyceride, Urea, Uric acid, TP, Albumin, and Globulin. AST, ALT, and ALP levels in the induced ascites group increased by 1.16, 1.35, and 1.16 times, respectively. When the chickens had induced ascites, the levels of all three hormones in the blood serum of broiler chickens increased significantly (P
