Usually at least 2 years. Do you have supplemental light for them this winter? They need at least 10 hours, I think, to keep laying.

One of our birds lived 11 years and she layed up until about the last two years. Most commercial concerns rotate their stock more frequently, say every few years. But their chickens are in battery cages, and not free range. I've been told when their legs get real white they are getting older and will not lay as much. I've also been told that if you can stick your finger by their pelvic bone you can see if it has room for an egg, or whether it's grown closer together, from not laying. I haven't tried it. Chickens don't really start laying in earnest until their 2nd spring.

commercial egg producers will have them for a year after they start laying. then they will start to molt and they get rid of them. day length does influence them and can make them lay alot longer. for the big boys the economics does't work out. i think that for a home farm three years"after they start laying" would be about right. having said that i'll also tell you that i had a chicken that i believe thought i was it's mother, followed me everywhere and hopped onto me whenever she could. she died of old age and it didn't matter to me if she was laying or not

Thanks for the your thoughts. Our chickens are a joy to us. I love to see them pecking and digging all over. I did see that during our last snowfall, they didn't go out at all. Guess they don't like snow. We have an indoor area for them that has two heat lamps and a regular bulb. There are roosting vines inside and also outside. The outside area is enclosed with a roof over it. Grape vines attached to the top gives them an area to roost outside also. The door is left open in the day so they can free-range.
It sounds as if we can keep our chickens another year or two before we need to replace them. We are not a commercial operation by any means but have several people coming to buy our eggs each week.