Found one of my leghorn hens wet and huddled outside of the pen this morning when I went to feed. She never moved when I walked by just opened her eyes slightly. She won't eat and her comb is blue on the tips. My leghorns fly out of the pen and roost on the fence and not inside the coop. I brought her inside thinking that she might just have gotten to cold but I just checked on her and she passed. How can I prevent this from happening again?