We live on a total 9 acre property, but, only 3 acres is used by us. You know it sounds like so little, but it is not. About 1 acre is on a steep sloping part of the back pasture, with trees and underbrush, and potential for place for predators such as our local ravaging coyotes to hide, so we took some fencing an fenced behind the barn, and our current 18 chicken flock has about 1 acre to roam of their own, all fenced in away from our plot of 1 acre (I don't want chicken doo in my outdoor area). It is a lot, they can happily spread out and will never be able to undo all that pasture and make it muddy and unsuitable, plus I know I can easily add plenty more layers if I wanted and still be ok.
They also love it if I let the grass get long, they go along and run their closed beaks on the stalk and gather the seeds. However, I have feeders set up inside with plenty of egg layer ration, and also they get veggie leftovers (including baked potato skins), leftover rice, wilted salads, dried up bread (not moldy), stale grain cereals, leftover cooked oatmeal....we have little kitchen waste and this helps them have a good healthy diet and lots of good eggs.
Be sure you give them some oysters shell for calcium (super cheap in 50# bags at feed stores), they need it to have strong egg shells and it also prolongs their egg laying years. You just spread some out on the ground (about 5#) and they'll know what to do with it.