The present investigation was carried out on cockerels of two poultry breeds; Fayoumi and Rhode Island Red at different ages, obtained from poultry breeding farm, Faculty of Agriculture, Assiut University. The increment in the mean testicular weight was three-time higher in Fayoumi than in Rhode Island Red.
The volume density of the intertubular tissue as well as the number and size of the Leydig cells were higher in the testis of Fayoumi than in Rhode Island Red cockerels. On the basis of the morphological eviden ces, it was concluded that the reproductivity expected to be higher in Fayoumi cockerels than in the Rhode Island Red.