The aim of this study was to identify the optimal turning duration of Dandarawi hen incubated eggs on embryo mortality, hatchability, one-day chick weight and viability of chicks at 14 days of age. Collected eggs from Dandarawi hens at 36 weeks of age were stored for 7-d at 16°C and 75% RH and then were incubated for 21-d under standard incubation conditions using different turning durations. Eggs were turned from d 2 till d 12 (T12), 13 (T13), 14 (T14), 15 (T15), 16 (T16), 17 (T17) or 18 (T18) of incubation. Eggs were turned once per hour through an angle of 90°. Three replicates of 100 eggs each per turning treatment per 3 incubation settings (total of 2,100 eggs) were studied. The results showed that turning eggs till d 12 of incubation of Dandarawi hatching eggs gave better hatchability and lower embryonic mortality and pepping chicks than turning eggs till d 13, 14, 15, 16, 17, and 18 of incubation. One-day old chick and chick weight as a percent of egg weight did not differ between the different treatments of turning duration. Viability of chicks at 14 days of age were lower (P≤0.05) for eggs turned till d 16 and 17 of incubation as compared to the other treatments which did not differ significantly.
In general, turning Dandarawi hatching eggs till d 12 of incubation gave better hatchability and lower embryonic mortality and pepping chicks. Moreover, it did not have any significant effect on the viability of chicks at 14 days of age.