Dietary anthocyanin-rich roselle extracts did not affect the bird’s growth and carcass traits. However, its addition had many beneficial effects, such as improving the bird’s intestinal morphology indicated by increased villous height and VH: CD ratio, indicating better nutrient absorption. Moreover, it improved the birds’ metabolic functions indicated by increased T4 and growth hormone with no effect on the glucose and leptin hormone. Dietary ARRE lowered the triglyceride level and improved the antioxidant activity by increasing the TAC and SOD activity and reducing the MDA level. ARRE addition improved the immune status by increasing the serum levels of IL10 and lysozyme and upregulating the IgG immune expression in the spleen. Furthermore, its addition increased the n-3 PUFA content in the breast muscles, increasing consumer acceptance. The optimum inclusion level of ARRE was 280 mg Kg−1.