my mom has a tiny coop, but only two hens. they refuse to roost and instead sleep in the nest box, funny thing is they never poop in there, they go out and land a pile as soon as they get out side. if you have a small coop it may be your roosts are to low to the bottom like my moms, or small coop. it you have a bigger coop then I sugest you take them out of those nests and put them on the roost after dark. keep doing it until they have the right idea. also what are you suplying for a roost? some times folks use branches and some birds do not like them . I use a 2x4 flat side down, they sit on them and they rest well. ( we also carpet them lol so they feet do not get cold in winter.