Interactions between egg storage duration and broiler breeder age on egg fat content, chicken organ weights, and growth performance.

Egg storage and breeder age are between the most important factors affecting egg lipids, chicken quality, and posthatch performance. To evaluate these factors, including their interaction, the impact of egg storage duration (5, 12, and 19 D), and breeder age (47 and 67 wk) was investigated in Arbor Acres broiler eggs and chickens. Total yolk fat content, chicken organ development at hatch and at 6 D of age, and posthatch performance (at 7 D and 35 D of age) were determined. Total fat content in fresh yolk was lower in 12 and 19 D stored eggs than in 5 D stored eggs (Δ = -2.42% on average). In hatchlings, the heart percentage was not affected by storage duration in the younger flock but was higher after 19 D than after 5 and 12 D of storage in the old flock (Δ = +0.09% on average). Residual yolk weight was higher after 12 D egg storage than after 5 D egg storage (Δ = +1.7 g), with 19 D egg storage in between. Liver and intestine percentage decreased with storage duration. Residual yolk weight (Δ = +1.09 g) and liver percentage (Δ = +0.18%) were higher in old breeders than in younger breeders. At day 6, chicken BW, yolk free body mass, liver percentage, and intestine percentage interacted between egg storage duration and breeder age with the strongest effects in chickens from older breeder after 19 D of storage. Heart percentage was lower after 19 D compared with 5 and 12 D of storage (Δ = -0.05% on average). Feed intake and feed conversion ratio were higher between day 0 to 7 and 0 to 35 after 19 D than after 5 D egg storage (Δ19-5 D = +12 g and +199 g; +0.11 points and +0.09 points, respectively). It can be concluded that when it is needed, eggs from younger breeders should be stored for a prolonged period (≥12 D) rather than those from older breeders.