Eggs should be gathered from the coop every day unless you're planning for chicks, so you might think hens lay an egg each day. While some hens approach that average at their peak, eggs are gathered daily to keep hens laying -- even when they don't always produce an egg.
When the weather is warm and a hen bred for egg production is healthy and in her prime, she'll lay one egg on average every 26 hours. If she were able to keep up this pace all year long, she'd produce about 337 eggs -- but most hens don't lay as many eggs in the winter as they do during the rest of the year. This brings the average down to around 265 eggs per year for a normal production hen, or a little more than two eggs every three days.
The number of eggs any hen will produce depends greatly on her breed. Some breeds of chickens have been groomed for egg production, with selective breeding ensuring the hens will lay as many eggs as possible. Bovan goldline, Rhode Island red, legbar and light Sussex are all types of chickens that have been bred for rapid egg production. Bovan goldline may lay as many as 320 eggs per year, while Rhode Island reds, legbars and light Sussex produce an average of 220 per year. Other breeds have been created for show or meat and may not lay as many eggs. For example, show-line Orpington hens may lay about 80 eggs per year.
Most breeds of hens start laying eggs when they're 20 weeks old but don't produce regularly until about the 30-week mark. This means for the first seven months, the hens won't come anywhere close to an egg a day. The next two years is when hens are at their peak, with commercial egg breeds averaging an egg every 26 hours. After two years, however, production starts to decline. This happens at an average rate of 10 percent each year. Many laying hens are replaced when they're two years old to keep production at its peak.
It's not necessarily the cold weather that comes with winter that affects the number of eggs a hen produces, but the lack of daylight. A hen needs at least 17 hours of daylight to produce eggs at her peak rate, and at least 12 hours to lay eggs at all. As the days shorten, she'll produce fewer eggs, and when they start to lengthen again in spring, she'll produce more. Humans can alter this natural production schedule, however, by adding lights to the coop, which fools the hens' bodies into continuing to produce eggs even during short winter days.
An unhealthy or stressed hen will not produce as many eggs as a healthy, happy chicken. Poor nutrition or disease can cause production to drop, or the hen may lay eggs that aren't properly developed, with soft or misshapen shells. A stressed hen that has been handled too much or is scared by predators may also temporarily produce fewer eggs. Also, some hens may decide to hide their eggs rather than laying them in the coop, which will look like a drop in production.