Eggs: Unfertilized Eggs

From a discussion regarding urban egg production during an excellent Father's day and retirement party weekend.

We were having trouble understanding if a chicken would lay eggs without a rooster around to fertilize the eggs. It turns out most commercial hens go about laying eggs without ever seeing a rooster.

This seems to be a good round-up of egg production and fertilization.

Hens begin laying at 18 to 20 weeks of age and a healthy chicken will
lay about one egg a day. A hen does not need a rooster to lay eggs
and eggs are produced in response to day light patterns. The eggs we
buy in the store are not fertilized (they don?t hatch). The size of
the egg is dependent on the age of the hen. Older birds lay larger
eggs.