More info: Female chickens are called pullets for their first year of life or until they begin to lay eggs which for most breeds is around 20 weeks of age. Some chicken breeds lay eggs daily, some every other day and some once or twice a week.
Things that may interfere with with laying routines include molting, reduced daylight hours in winter, temperature extremes, illness, poor nutrition, stress, and lack of fresh water. Hens usually return to normal laying habits when the causative problem is rectified.
Most hens are productive layers for two years before declining in production, but some continue to lay eggs for several years.
Hens will lay eggs whether or not they have ever seen a rooster. Roosters are necessary only for the fertilization of eggs.