title: Relationship of parents' age, hatching egg weight, and shell quality to day-old chick weight as influenced by oviposition time.
abstract: This study was conducted with 840 eggs from commercial breeder hens to determine relationship of parents' age, egg weight, and to oviposition time and shell quality and day-old chick weight. Results indicate that eggs laid in the afternoon were significantly smaller with significantly better shell quality than those laid in the morning (64.1 vs. 64.5 g and specific gravity of 1.077 vs. 1.074, respectively). Also, chicks from afternoon eggs tended to weigh significantly less than those from morning eggs. However, the egg weight: chick weight ratio was not significantly affected by oviposition time; it was the same for morning and afternoon eggs (70.7 vs. 70.1%). The linear relationships between egg weight, age, and chick weight or between egg weight and chick weight were strong (R2 = .78 to .91), but the associations between specific gravity and chick weight were weaker (R2 = .28 to .24). It was possible to use both parents' age and egg weight or egg weight alone to predict chick weight for chicks hatched from morning and afternoon eggs.
mesh_terms: D000375:Aging; D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000502:physiology*; D004528:Egg Shell; D005260:Female; D010058:Oviposition; D013997:Time Factors