There are many different types of incubators, but the success of artificial incubation depends more on the knowledge and skills of the person using the equipment than of the sophistication of the incubation equipment. It is important to have a basic understanding of the egg to successfully artificially incubate eggs. The egg must contain all of the nutrients necessary to sustain a growing embryo until hatching. The shell contains pores that allow respiration of moisture and gasses through the egg. These pores can also allow bacteria and other pathogens into the egg under certain conditions.
Eggs have two shell membranes, the inner and outer shell membranes.
At the area of the air cell, these two membranes are separated. If the egg is opened during an assisted hatch over the air cell, the inner shell membrane will be visible covering the chick. The egg white, albumen, consists of three proteins. Thick and thin albumen and the chalazae, which are two strands of thick albumen, connect to the shell membranes. These act to keep the yolk in the center of the egg.