In this study, a total of 36 ducks were utilised. Serum hormonal parameters like T3 and T4 were estimated with the standard procedure of Radio Immuno Assay (RIA). The average serum triiodothyronine level in 2 weeks old ducks was 2.706 ± 0.049 nmol/L. The mean serum level of thyroxine in 2 weeks old ducklings was 53.981 ± 0.590 nmol/L and in 40 weeks ducks was 71.198 ± .337 nmol.L.