The present study was implemented to provide comprehensive information on the developmental sequence of the proventriculus and ventriculus of Muscovy ducks by gross examination, macro-micrometric analysis and by using light microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). Samples from 55 healthy post-hatching Muscovy ducks of both sexes ranging from 1-60 days old.The difference between the examined age stages may be related to the feeding strategy (behavior) and the functional adaptations from the young to the older ages