The current research was completed to examine the impacts of dietary enrichment with zinc oxide and stocking density on performance, plasma concentration of thyroid hormones, corticosterone(cort) and immune response and antioxidant status in cobb 500 chicks. Experimental treatments were ordered in a 4× 2 factorial plan structure with 4 degrees of included dietary zinc oxide and 2 degrees of stocking density (11.90 chicks/m², normal stocking density, or 16.66 chicks/m², high stocking density,). Zinc levels were 0.0, 40, 60 and 80 mg/kg diet. Elevated level of zinc (80mg/kg diet) positively affected FCR while LBW, BWG and feed intake were slightly improved compared with the control one. Additionally, Blood plasma concentricity of "total protein (TP), albumin (Alb), total lipids (TL), cholesterol (Chol), high density lipoprotein cholesterol (HDL) and low-density lipoprotein cholesterol (LDL)" did differed significantly between the control and zinc-enhanced groups. Moreover, zinc oxide enhancement in the diet could improve thyroid hormones. Also, plasma Cort levels were significantly inferior at zinc-enhanced groups as contrasted with the control one. Moreover, enhancing zinc had a huge constructive outcome on SOD, MDA and immune response titers against NDV and AFV. The typical stocking density has better effects on performance and plasma levels of Cort, TP, TL, MDA and NDV to those of the high stocking density. Stocking density did not influence "T3, T4, Alb, Chol, LDL, HDL". The results of the present examination show that enhancing zinc oxide to broiler diets has a beneficial effect on productivity, blood parameters and immunity in cob 500 chicks.