I have chickens and while the eggs are great, what you have is new pets that also happen to produce eggs as a side-effect. (Assuming you live in a city and not on a farm) You treat them like any other pet. Chickens will live 3-10 years. One of my chickens died a year or so after she stopped laying, another chicken is now 10 and lays one or two eggs a year but is otherwise looking as healthy as they day we got her. I suppose you could kill them or even try to eat them but most layers are pretty skinny and would not make a great meal.
