In present study, effects of peripheral administration of ghrelin antagonist [D-Lys3
] GHRP-6 on chicken performance, thyroid hormone level and serum biochemical parameters were investigated. The results indicate that ghrelin antagonist [D-Lys3] GHRP-6 reduces feed intake and body weight. With regard to increase in T4 level, it can be inferred that [D-Lys3
] GHRP-6 may increase metabolic rate, lipolysis and weight loss, which is similar to results obtained in mammalian species.