I have a small flock of 16 birds. Some Bielefelders, Barnevelders and a couple of cream leg bars. They are approx 7 weeks old. We moved them from their brooder to the new coop around 5 days ago. Since then they've been sleeping in a pile on the floor. It's a little chilly in the coop, low last night was -1C. When I opened the door this morning, one of the Barnevelders was dead, pressed flat right against the door. All the other chickens appear fine, no injuries on the one who died. Just flat and very cold. I'm wondering if she got 'dog piled' by the other chickens? It's a big glass door of that matters, they seem to like to gather at it and look out. I'm a pretty sad chicken owner this morning, definitely was not expecting this... Any ideas? And how do I get them to sleep on the roosts and not the ground? Thanks so much for any help!