Morphology of the oviduct in Chukar Partridge (Alectoris chukar) during pre-laying and laying periods

This study was conducted to investigate the structural components of the female reproductive structures in Chukar partridge during the pre-laying and laying periods. The left oviduct was convoluted and muscular in the pre-laying and laying periods, but severely convoluted in the laying periods. Both had five regions: infundibulum, magnum, isthmus, uterus, and vagina. The infundibulum had two parts: the anterior half was large and funnel-shaped, and the posterior part was tubular-shaped known as the neck part. A fold was noted at the neck sections of the pre-laying (pre-laying was very thin and translucent) and expanded in depth toward the magnum, isthmus, and uterus (laying). The magnum s internal mucosal surface was oriented longitudinally. Pre-laying mucosal folds and invagination were less prominent, but during-laying folds were larger, more invaginated, and separated by indentations. The isthmus joined the magnum to the shell gland. The mucosal folds appeared larger, longer, more prominent, and longitudinally orientated in the laying than in the pre-laying. The uterus has two parts: an anterior tubular portion and a posterior pouch-like portion. Its walls were the thickest and widest in the oviduct. The uterine wall is thickest, broadest, and most distended during laying. Its inside surface exhibited circular leaf-like mucosal folds. The vaginal mucosal folds were organized differently and appeared white. The vaginal sphincter muscle in the early section of the vagina is responsible for releasing the egg from the cloaca into the external media.