Low Relative Humidity During Incubation

What Happens to the Embryo?

Carla van der Pol, MSc.

During incubation, an avian egg loses a certain amount of weight through water evaporation because of the difference in water vapour pressure between the egg and its surroundings. Evaporation from the egg is essential to create an air cell sufficient to start embryonic lung ventilation after internal pipping. When too little water is lost at the time of internal pipping, the embryo is not able to start breathing because the air cell will be too small. Consequently, the embryo may suffocate in the egg or struggle to hatch. Hatchability can, therefore, be negatively affected when too little water is lost.