Are their combs red? Do you have any windows in your chicken coop so they get as many hours of light as possible during the day? Are you feeding them a high protein layer feed, a calcium source such as crushed oyster shells, grit, and of course plenty of water? Could they be eating the eggs? Put some plastic or wooden nest eggs in there and see if they try to eat them.
I have tried all of that. They are out in there run all day and none are eating