Quercetin was fed to groups of broiler chickens at concentrations of 200, 400, and 800 ppm, and a control group was supplemented with a basal diet. Results revealed that quercetin dietary supplementation numerically improved the growth performance traits and significantly increased (p Clostridium perfringens were decreased (p Lactobacillus counts were increased (p SOD1), glutathione peroxidase (GSH-Px) and nutritional transporters, including glucose transporter 2 (GLUT2), peptide transporter 1 (PEPT1), and fatty acid synthase (FAS) genes, were significantly upregulated in quercetin-supplemented groups. Quercetin enhanced intestinal morphometry. We can suggest quercetin supplementation in broiler chickens by levels between 200 and 400 ppm to enhance their development and gut environment.