During incubation embryos produce carbon dioxide. Ventilation is required to remove carbon dioxide and maintain the correct oxygen levels. Ventilation is supplied automatically with a fan and adjustable air holes. Air holes are adjusted by turning the vent to increase/decrease the amount of air in/out. The amount of ventilation required will depend on egg size and quantity.
Never close air holes.
Always keep air holes fully open during hatching period.
Never breed animals in your incubation room.
Be sure incubation room is well ventilated.