Microbes in an incubator can significantly reduce hatchability. Cleaning and disinfecting equipment must be standard operating procedures. Disinfect incubators, hatchers and their racks with quaternary ammonia or a commercial disinfectant after each hatch.
The day eggs are set let stored eggs warm to room temperature for 4 hours to 8 hours before setting them in the incubator. If you place cold eggs in a warm, humid incubator, condensation will form on them and lead to possible contamination or suffocation.
Once the eggs are in the incubator, do not adjust the temperature or humidity for a few hours, unless the temperature exceeds 39°C. After 4 hours, make proper adjustments. The final temperature should vary only .5 degree above or below 37.5°C. The temperature of incubators with- out circulating fans fluctuates more than incubators with circulating fans. If the temperature does not exceed 39°C, the hatch should not be harmed.
Set the small end of the egg lower than the large end in the incubator. A developing embryo orients so that the head develops toward the air cell, which is in the large end of the egg. If the small end is higher than the large end during incubation, a chick’s head can orient away from the air cell of the egg and not hatch.