Most of the battery hen rescues state when you take on the hens - they are spent hens, looking for kind, forever homes - which they deserve after being cooped up in a hell hole for a year. They will tell you that the hens should lay, but the eggs are a bonus. If you are looking to make a profit from your egg laying birds, then quite frankly ex battery hens are not the way forward.
You know what they say about a Dog is for life, not just for xmas. Well, the same goes for my ex batts - some are old and wobbly, but they will live out their time here in my fields. Yes, they cost me a fortune in feed, but during the summer they do on the whole lay well and that covers their feed through the year.