Research Note: Effects of turning and short period of incubation during long-term egg storage on embryonic development and hatchability of eggs from young and old broiler grandparent flocks

Longer egg storage times (>7 d) are common in broiler parent and grandparent hatcheries to obtain the requested flock size. However, prolonged storage is known to decrease hatchability. The aim of this study was to investigate the effects of turning and short period of incubation during egg storage (SPIDES) for 14 d on the stage of blastoderm development, embryonic mortality, and hatchability of eggs from young and old grandparent flocks. Hatching eggs were obtained from Ross female line grandparent flocks aged 29 wk (young) and 58 wk (old). Eggs were stored at 15 degrees C, and turned 90 degrees 0 or 4 times daily during storage. On day 5 after egg collection, the eggs were either held in the storage room (control) or subjected to SPIDES treatment. The development of the blastoderm in sample eggs was determined immediately after collection on a farm and again after the SPIDES treatment. Each of the 8 subtreatments was tested on 6 replicate trays of 150 eggs (900 eggs per subtreatment) with 7,200 hatching eggs set in a single-stage setter and hatcher for the trial. The stage of blastoderm development was advanced by the old flock, by SPIDES, and by turning 4 times daily during egg storage (P <= 0.05). There was a significant interaction effect of flock age x turning during storage on embryonic development, which suggested that turning advanced the stage of blastoderm development only in eggs from the old flock (P <= 0.05). Eggs from the young flock had a better hatchability than eggs from the old flock (P <= 0.05). Hatchability was increased by turning 4 times/day during the storage period compared with no turning because of a decrease in the percentage of late embryonic mortality (P <= 0.05). SPIDES decreased early and late embryonic mortality as well as the percentage of second-grade chicks (P <= 0.05), which increased the hatchability of fertile eggs at both flock ages (P <= 0.05). The results of this study showed that a combination of turning eggs 4 times daily along with one SPIDES treatment during 14 d of storage resulted in the highest hatchability in both young and old broiler grandparent flocks.