I hear it all the time, my hen stopped laying. But armed with some information about a hens laying cycle this isn't such a mystery anymore. A pullet begins laying eggs at 18 to 20 weeks of age. She reaches peak production at about 35 weeks. Peak egg production lasts about 10 weeks and after that her egg production slowly begins to decline.
A top egg laying hen’s annual egg production is more than 10 times her body weight. The average commercial battery hen lays about 265 eggs per year, with backyard breeds laying fewer. In most cases, the more exotic the breed, the poorer the egg production.
All hens will stop laying eggs for a variety of reasons. Different things affect hormone levels, which change the condition of the ovary and oviduct, the organs responsible for egg production. The result of these changes is the cessation of egg production. The most common event that affects egg production is decreasing day length. Hens are sensitive to day length, and particularly to the direction in which day length is changing, when it comes to laying eggs. Declining day lengths discourage egg production. It is not unusual for a flock owner to have hens go out of production in the latter part of summer and in the fall because the days are getting shorter. Commercial egg producers avoid this problem and maintain egg production year round by using artificial lighting to give hens a long day length no matter what the season. You can do the same thing if the flock roosts inside a building by keeping lights on long enough to simulate an appropriately long day length. A good rule of thumb is that the total length of light per day, both artificial and natural, should be no shorter than the longest natural day length the hens will experience. Therefore, the amount of artificial light needed will be minimal in summer and greatest in winter.
Other things that effect egg laying are disease, broodiness, poor nutrition, and stress. But even under the best circumstances all good things must come to an end.