I am new to the world of backyard chickens. I have 6 chickens. 3 barred rocks, and 3 rhode island reds. They are about 8 or 9 months old. This is their first winter. They all are healthy "happy" chickens. Minerva though, hasn't came out of the coop or even off the roost this morning. They have a nice coop. It's cold. 0 or possibly a little lower last night. Their coop does not have heat. All of my other girls are running around the run doing chicken thing, but she is just sitting in the coop. Is she OK? If it were a cold issue, wouldn't they all be cold? I'm kind of worried. I love my chickens and try to give them the best1 Thanks in advance for any advice!