My cousin only feeds table scraps, scratch grains (occasionally) and lets them free range a cow pasture. They lay just fine but he has more than 1 acre per bird with plenty of cow Patties to attract bugs even in winter They also eat all the seeds that fall out of cows hay and access to gardens come fall/Winter. Giant compost piles etc. If you have the perfect conditions you can get away with it. If you have a typical backyard then production will drop drastically. Certain breeds do flourish in those conditions and others will not.