Influence of temperature stimulation during the last days of incubation on hatching result of broiler chickens
A total of 9883 eggs of the ROSS (308) strain were incubated from day 1 to 17 under normal incubation conditions (37.2 - 37.4°C) and then sorted in three hatch incubators in Trials 1 and 2 or in two hatch incubators in Trials 3 to 6. In the first hatch incubator the temperature was 37.2 - 37.4°C. The temperature was increased by 1°C over standard (38.2-38.4°C) in the 2nd hatch incubator and 1°C over standard for 2 hours daily in the 3rd hatch incubator from day 18 of incubation until hatch. In all trials the 1-day chickens were sorted by sex. Random sampling of chicks (30 males and 30 females of all incubators) were analysed by the Pasgar score. The results of the first two brooding trials showed that the continuous increase of temperature in hatch incubator 2 by one degree Celsius did not change the percentage of hatched chicks in comparison with the control. In contrast the statistical evaluation of the six hatches from incubators 1 and 3 gave a statistically firmed higher percentage of male one-day chicks as females. The mean Pasgar score of 9.6 was the same for both female and male chicks.