I have the same problem with mine "roosting" in the nesting box. I may leave them too it over the winter months as, like us, I'm sure they would appreciate a bit of extra heat in the cold weather. I have 4 light sussex that only seem to want to sleep on the bottom of our coop - they never roost on the available roosts. Is this typical of this breed? I have a small portable roost (12" long x 4" high) which I've put in the coop and the rooster uses it. His "girls" cuddle up around the bottom of this roost though. I have a branch out in the run for them to roost on in the daytime and they don't even seem to like it, preferring to just sit in the grass! They also don't scratch like our other breed does. I thought all chickens scratched!