So we used an old barn to mark a coop, there is a 6-8" ledge around the whole coop about 24" off the ground (foundation of old barn). I built a nice roost with 2x4's, however the chickens refuse to use the roost they just chill on the ledges all night long, they're only 17weeks, will they eventually use the roost I built or should I block off the ledges and kinda force them to use the roost that is made?