The rare chicken can live up to 20. People have posted about having chickens in the 15+ years old.
How long they lay just depends on the breed and the individual bird. Some people have posted that their geriatric hen have layed 2-3 eggs per week. I have a 5+ yo GLW that has pretty much stopped laying.
I have a golden lakenvelder hen who is at the youngest 10 yrs old. I didn't have her as a baby, and the lady
I got her and her sister from had them a couple of years. Her sister died over this last winter, but she still lays eggs, sometimes I get 2 or 3 a week other weeks I get none. ( I think there's an egg eater in there with her and I haven't found out who yet)
all of my chickens are free range and only loose them at night and almost all have died from natural causes unless your feeding them feeding them special medication or they are bred that way they are living longer than any of mine have