I have 2 month old chickens who seem to prefer to sleep outside of the coop even tho there is a perfectly cosy,dark sheltered position for them to roost. The coldest it gets here is about 15 degrees and no frosts. Predators are also minimal. There is a street light that shines in on there run and this is where they seem to want to rest. Is there a problem with this or should I just let them sleep where they want to.???