I can’t fathom why they do that. It isn’t temperature related because they do it in the summer too.I wonder why mine spread out? It's warm here, but Alex is in California, too. In fact, it's probably a few degrees warmer where he is. Though, Alex's weren't crammed tight like yours, RC!
Before the little roadrunners were allowed into the big roost they wanted to get as close as possible and flew up to the top of the open window. I really wasn’t expecting that and have roosts all over the Chicken Palace at the same height as the big roost and they could have chosen any one of those!
No explaining what is in their heads!