The egg production rate of your hens can vary from one person's experience to another. There are many variables for this, including and not exclusive to: history of sickness, wormy, care, lighting, climate, geographic location, housing condition, crowding, feed consumption, water conditions and consumption, nutritional care, bedding, sunlight availability, number of cockerels with the flock, noise condition, nesting conditions, roosting conditions, winter housing conditions, summer housing conditions, predator harassment, whether or not you are breaking up setting hens and other conditions.
6-18 months is considered the first laying year. The second laying year the hens usually lay a slightly larger egg, however production will be 10%-20% less.
The third and fourth year can dramatically decrease. Most flock owners will harvest the hens after 1-2 years of production and start over with younger stock. This is the most economical strategy because it allows for less feed consumption and keeps disease issues down.
Generally in the late summer or fall hens will do a natural molting process and produce very few eggs during this time.