Could the fact that w feed only spent grain to our chickens make them not lay? They are free range and get scraps but we have 35 layers and get only 12-15 eggs a day. We have looked like crazy around property and no luck finding any. We closed them up for 31/2 days and got less than we were getting. So frustrated!! Any advise? We are thinking of getting some layer crumbles and see what happens.