Personally, I would block off anywhere you do not want them to be. I ended up with a few bits of frostbite when my 4 hens jammed into a single nest box when the temps dropped super low. The ventilations was so good in the next box for 4 of them.Hi there! I know this is an older post, but I’m hoping someone can chime in with advice. Some of my chickens sleep in the eaves (the open space for ventilation at end of rafters, 10 ft long.) So they sleep on hardware cloth. They access the space via a 2x4 wall separating their coop from storage area inside the barn (the wall is the same height as the highest roost). They have two 10 foot roosts made of 3” logs; but no one sleeps on the lower one, just the higher one (approx. 5’ & 6.5’ off the floor). My question is will they know enough to not sleep in the eaves if it gets too cold? Or should I put up chicken wire to block their access? (Forcing them to use the lower roost bar?)