PHYSIOLOGY AND REPRODUCTION: Embryonic Development from First Cleavage Through Seventy-Two Hours Incubation in Two Strains of Pekin Duck (\u3ci\u3eAnas platyrhynchos\u3c/i\u3e)

Embryonic mortality is a significant problem plaguing the commercial duck industry worldwide. Yet, an objective means to stage development of the duck embryo is lacking. Such a staging procedure, which is described in this study, is essential for the critical and reproducible assessment of embryo development. The morphological features associated with duck embryo development are very similar to those of the chicken, although the duck embryo develops more slowly. The staging scheme presented here provides objective morphological criteria describing the embryonic development of the duck