Broiler hatching eggs from two young (30 and 31 wk) or two old (52 and 53 wk) breeder flocks were stored for 3, 7, or 14 d at 18 C and 75% RH while being turned 0, 4, or 24 times per day in two experiments. Apparent fertility and hatchability of total eggs differed with flock age in both experiments, but the effect was greater in Experiment 1. Hatchability of total and fertile eggs were decreased with flock age in Experiment 1 (31 and 52 wk flocks), but only hatchability of total eggs was decreased in Experiment 2. Hatchability of fertile eggs declined with length of storage period in both experiments with the most obvious effect observed in eggs stored 14 d. There was an increase in percentages of early and late embryonic mortality with length of storage period in both experiments. Hatchability of fertile eggs was increased by turning 4 or 24 times per day during storage in Experiment 1 or by four times per day, with 24 times per day intermediate, in Experiment 2. There were no storage time x turning in storage interactions. A significant interaction of flock age x turning in storage for hatchability of fertile eggs in Experiment 1 suggested that eggs from an older broiler breeder flock that exhibit reduced fertility benefited more from turning during storage than did eggs from a young broiler breeder flock.

Two experiments were carried out to examine the interaction of egg storage period, egg position during storage, and turning frequency during subsequent incubation on fertile hatchability and embryonic mortality of broiler hatching eggs. Broiler hatching eggs from breeder flocks at 62 and 60 wk of age were stored for either 3 or 14 d at 18 degrees C and 75% RH in either the normal large end up or inverted small end up (SEU) position and then turned either 24 or 96 times daily to 18 d of incubation in 2 experiments. The longer storage period decreased fertile hatchability, whereas storage in the SEU position improved fertile hatchability in both experiments. There was a significant storage position x length of storage period interaction in both experiments due to better fertile hatchability for the SEU eggs stored 14 d but not 3 d. The 96-times turning frequency numerically improved fertile hatchability in both experiments. A significant storage period x turning frequency interaction in experiment 1 was related to a 6.6% increase in fertile hatchability of 14-d stored eggs due to increased turning frequency. A similar numerical increase of 4.9% was observed in experiment 2. These data show that the detrimental effects of a long storage period may be practically ameliorated by either storage in the SEU position or by an increased turning frequency during subsequent incubation.

The effect of turning angle (from vertical) and the interaction with turning frequency during incubation on fertile hatchability, embryonic mortality, and the incidence of embryos with head in the small end of the egg (malpositioned) was studied in 2 experiments comprising 2 trials each to determine if a turning angle of less than 45° could be successful. Hatching eggs from commercial broiler breeder flocks from 55 to 61 wk of age were utilized, and turning was for 18 d. Eggs were subjected to turning angles of 35, 40, or 45°, with a turning frequency of 24 times daily (24×) in Experiment 1. Turning angle had no effect on fertile hatchability. However, the incidence of separately enumerated, malpositioned embryos was increased by the 35° angle, compared with both the 40 and 45° angles in Experiment 1. Eggs were subjected to turning angles (from vertical) of 35°, with a turning frequency of either 24× or 96× daily, or 45°, with 24× turning in the 2 trials of Experiment 2. Turning angle and frequency had no effect on fertile hatchability or embryonic mortality, but the incidence of separately enumerated, malpositioned embryos was increased by the 35° angle with 24× turning, compared with the 35° angle with 96× turning, and the 45° angle, with 24× turning, in Experiment 2. These data demonstrated that the incidence of malpositioned embryos was increased by a reduced turning angle, but that this effect was ameliorated by a concomitant increase in turning frequency.

Two experiments, which included 3 incubators, were carried out to investigate the effects of egg weight and position relative to incubator (setter) f

The effects of heating of eggs during storage, broiler breeder age, and length of egg storage on hatchability of fertile eggs were examined in this s

Hatching eggs from broiler breeder flocks at 37, 41, 59, and 63 wk of age were stored for 1 or 2 d at 18 C and 75% RH and then turned 24, 48, or 96 times per day from 3 to 11 d of incubation. All eggs were turned 24 times per day from 1 to 2 d and 12 to 18 d of incubation. Fertile hatchability was better at 37 and 41 wk of age than at 59 and 63 wk of age due primarily to increased early dead embryos. Fertile hatchability was increased by turning 96 times per day compared to either 24 or 48 times per day. This improvement was due to a reduction in late embryonic mortality. There was no significant interaction of flock age x turning in storage for fertile hatchability or embryonic mortality.