yeah thats true maybe they all want to be near the open window to feel the cool draft diffrent breeds need diffrent maintenance maybe some needed to cool and some like the warmth also since these are hierarchy birds it may be that they roost depending on their levels i.e. top hen all the way to...
actually as far as I know and learned as a newbie chickeneer :) they will roost at the highest point they can and if their huddling together its to keep warm :) I have three levels of roost in my coop and they seem to either use the top one or the edges of the nesting boxes :)