How Does a Chicken Lay an Egg?

Coming of Age

The average age for hens to begin laying is 5 to 7 months. Your hens will lay small eggs at first and will continue to lay larger ones as time goes on. Young hens will begin by laying one egg every 3 to 4 days. As your hen reaches around 30 weeks, she will be able to lay two eggs every 3 days. Your hens will be at their top laying potential at 1 to 2 years of age. Hens will lay for a period of 4 to 6 days and then take a rest. Some hens will take as little as a day to rest. Your hen will lay eggs with or without a rooster.

Creating the Egg

Chickens produce egg cells just like humans. Chicken oocytes are packaged with the yolk and are contained together inside a thin membrane made of protein. These packages are released one at a time into the oviduct, the tubular "assembly line" leading from the ovary to the outside. The oocyte will linger in the beginning of the oviduct for about 20 minutes waiting for fertilization. If no sperm are present, the egg will proceed down the line. In the final journey down the line, the egg white will be added. The shell membranes are next and are followed by the construction of the shell.

Laying the Egg

All birds have a common opening for reproduction and elimination. It is called the "vent." All passageways leading to the outer rear of the chicken come together in a chamber called the cloacae. When the hen is ready to lay her egg, she will turn part of the cloacae and oviduct inside out. This way the egg never comes in contact with the walls of the cloacae and stays clean. The egg will emerge on the outside of the chicken. The emerging egg also closes off the intestine so nothing leaves the body no matter how hard the chicken strains. So blame the chicken's dirty feet if you ever find a dirty egg.