We are going to use a metal shed for our coop. The floor of the shed has metal rails. Usually a plywood floor is applied on top of the rails. My question has to do with using sand on the floor of the coop. Don't know if we should just pour a load of sand right over the rails, or apply the plywood floor over the rails, then pour the sand on top of the plywood. One consideration would be that we would like worms and beneficial bugs to be accessible to the chickens up through the sand from the dirt below. The shed does not leak, so the floor will stay dry. This is the 10 ft. x 7 ft. shed: Any thoughts???