It is inevitable to obtain chicks from breeders of different ages in broiler fattening. However, breeder age has an effect on eggs. There is no detailed study on the changes in mineral levels in eggs and bones of these effects. Therefore, the aim of this study examines how mineral levels of shell, albumen, egg yolk, and bone, embryonic development and bone characteristics change according to the breeder age. A total of 370 fresh hatching eggs were obtained from Ross-308 breeders at 2 different ages (25 to 60-week-old). Egg, embryo, yolk sac and chick characteristics were determined. Morphometric parameters of bones of embryos at 19 days of age and chicks at hatch were examined. Mineral levels of albumen, yolk, shell and bones of embryo and chick were determined. Egg weight, embryo weight, embryo length, chick weight and chick length were higher in old breeder than those of younger one. Femur length, width and Seedor index of tibia, weight, width and Seedor index of metatarsus were found to be high in embryos at 19 days of old breeder than young breeder. There were differences in relative femur weight, tibia length and relative metatarsus weight of chicks at hatch. The mineral levels were high in the femur, tibia and metatarsus of embryos and chicks, in parts of the egg of old breeder. K, Ca, Mg, P, Fe and Mn levels in the eggshell were decreased during incubation. Ca and Mg levels were decreased in the yolk during incubation. K, Ca, Mg, P, Fe, Zn and Mn levels were found to be high in chick bones than those of bones of embryos at 19 days of age. The total embryonic death was found to be high in the fertile eggs of younger breeder group. No differences were observed in fertility, hatchability of fertile and set eggs according to the age of breeders. These data may be useful in designing in-ovo injections, formulating diets of broiler breeders and broilers and in preventing bone diseases in broilers.