Thyroid gland in birds is as vital as in other animals controlling metabolism, differentiation, growth and production. In birds a paired organ at the base of neck seen from second day of incubation. In female birds it is more important as the hormones directly effects the development of reproductive system thus effecting the production.So the normal development of this gland is of prime importance and any deviation or disturbance can effect the basal metabolism of the birds in turn affecting the production potential of the flock.