Some larger businesses fumigate incubators before setting eggs. Occasionally the incubators are fumigated briefly with lower concentrations of the fumigant while eggs are in the incubator. Do not fumigate eggs after the first day of incubation. Embryos are sensitive to fumigation between 2 days and 5 days of incubation. When eggs are fumigated at set, exposure of the eggs should be limited. Only trained individuals should use these techniques.

Remove eggs from storage and allow them to warm to room temperature for 4 hours to 8 hours before setting in the incubator. Cold eggs placed into a warm, humid incubator will become covered in condensation that will increase the possibility of egg contamination. Ensure that proper records are maintained so that eggs are turned a minimum of three to five times in a 24-hour period.

Failure to turn eggs adequately results in embryo death. Use of an automatic turner considerably simplifies the work and decreases human error during the incubation process.

Once eggs are in the incubator, do not adjust the temperature or humidity for a few hours unless the temperature exceeds 102 degrees F. After 4 hours, make proper adjustments. The final temperature should vary only degree above or below 99.5 degrees F. The temperature of incubators without circulating fans fluctuates more than incubators with circulating fans. If the temperature does not exceed 102 degrees F, the hatch should not be harmed.

The small end of the egg should be lower than the large end of the egg when set in the incubator. An embryo orients during incubation so that the head develops toward the large end of the egg where the air cell is located. A chick's head can orient away from the air cell of the egg if the small end is higher than the large end during incubation. An embryo oriented in the wrong direction will not hatch.