I have dropping pits under my roosts and I put them in all the 4X4' coops I make. I keeps the chickens from scratching in their poo. I just make them out of 2x4's and cover them with welded wire or chicken wire. The girls still walk all over them, and don't mind a bit. But I'm glad they aren't digging in that mess. I'd say that about 90% of the poop in the coop goes there. It stays way cleaner.