My birds have an enclosed run (except for the roof) and they were out in it yesterday while we were at work. My husband closed it up at 6 p.m. when he got home from work (dark for 30-45 minutes already). I went out at 8 after work to gather eggs. I talked to the ladies and collected eggs with a flashlight, but I did not count them. So, this morning I got kids in car to go to school and me to work, and I see a little red hen hunkered down beside the run. There was frost on her feathers, but she talked to me as I walked up. IT was a very heavy frost, probably the heaviest so far this year. It was 25 degrees. The grass around her was not frosted from her body heat I assume. So, I picked her up, she struggled a bit and then settled into the crook of my arm like normal. I took her into chicken house, she fluffed her feathers and kind of was slow moving, but I had to go to work, so I am here at work wondering about her. She had no sign of injury, her eyes were clear, her little comb looked good. And she was perky, just not moving fast. Poor dear spent the entire night outside, I am glad she wasn't a chicken nugget for anyone. But I am asking the experienced ones, is it likely she will have any issues with being out like that? They are not in a heated or insulated barn (very new just built for chickens, decent ventilation coop).