Chickens normally lay an egg in the morning, and each day thereafter it gets a little later. Sometimes the last egg is produced in the early afternoon, and when it gets too late, they take the next day off. Chickens never lay more than one egg per day.

The actual process of laying an egg happens like this:

1. The hen approaches her nest hesitantly at first, and then enters. She then sits quietly for quite a while – sometimes half an hour or more. At first she closes an eye or calmly puts a straw on her back, and then gets more excited. Now and then, the hen raises her tail and spreads the feathers of her bottom.

2. She has a small opening shaped like a horizontal slit under her tail. This opening is called the vent, and is about an inch wide. It is surrounded by a ribbed rim, and has skin and feathers all around it.

3. Suddenly the hen raises her tail, stands up with her feet wide apart, bottom feathers spread out and back feathers upright. As her vent opens a little, you begin to see a red membrane.

4. As the hen lowers her bottom, her vent widens rapidly and the rim is stretched further. The membrane forms a pinkish dome around the egg which is not yet visible at this stage.  

5. The vent is now wide open and the ribbed rim has become narrow and far stretched. Through the opening bulges a pink hemisphere of tissue revealing distinct blood vessels. Its top is pointed downward where a new opening arises. The egg appears as a much lighter-colored disk. Even brown eggs are much lighter than the surrounding membrane.

6. The hen strains at intervals. Each time, the egg comes a little further out. As it does, the membrane opens to form a red collar around the wider, middle portion of the egg. The membrane will protrude a little ways from the ribbed rim.

7. The moist egg pops out. Sometimes it will come out blunt end first, sometimes pointed end first. For a few seconds after the egg is laid, a small red cone still remains outside, but it is retracted almost immediately and the vent is closed again. The bird stands high above the egg and rests, beak open and panting after the heavy work.

The entire process (from rising to dropping the egg) is quite fast and is finished within half a minute. Therefore, it is hard to observe. After a while, the hen looks back, inspects the egg with her beak and leaves the nest under loud cackles. The hen then eats and drinks and goes her usual ways. She seems to have forgotten her egg completely.

From Laying an Egg – an interesting event!
Wiebe H. van der Molen