This study was carried out to investigate the effects of breeder age and hatching time on hatching performance, morphological changes in jejunum and post-hatch performances until slaughter age. A total of 544 eggs were obtained from two Ross broiler breeder flocks at 32 (young, Y) and 49 (old, O) weeks of age. Eggs from each breeder age were placed in 8 egg trays and incubated under standard incubation conditions. Between 480 and 504 h of incubation, eggs were checked individually to record hatched chicks. According to hatching time, chicks were marked and divided into two groups as early hatched (EH, from 480 to 485 h of incubation) and late hatched (LH, from 495 to 500 h of incubation). Sixteen chicks from each breeder age and hatching time were randomly selected at 3 h after hatching, weighed and sacrificed by cervical dislocation. Weights of residual yolk sac, heart, spleen and bursa of fabricius, lengths of digestive tract, jejunum, and villus height and width were obtained. Hatching performance was determined. Chicks from each breeder age and hatching time were reared up to 35 d. Body weight and feed intake were recorded weekly, then feed conversion ratio was calculated.