The chicken egg contains: yolk, 31%, albumin or egg white, 59%, 10% shell (approximate figures), yet the composition of water rises to 66%, the proteins in the egg would be the 13% the fat content is 10.5% and finally the ashes contain another 10.5%. Development begins in the ovary where the yolk is formed. There are many eggs in the ovary, each enclosed in a follicle. The yolk is deposited in concentric layers, and when the process is completed, the follicle ruptures and the yolk, wrapped in a membrane, as mentioned above, passes into the oviduct. It is formed and then the egg white shell, each process requiring several hours. During its passage through the oviduct, the egg is fertilized if there is sperm. After completion of shell formation, the egg exits through the cloaca. Placed under appropriate conditions of temperature, the fertile egg becomes chick in twenty one days. The rooster reproductive process is similar to that of mammals.