Today I went to let my chickens out and feed them and one of my girls did not come out of the hen house. I could see her moving and hear her making noise so I wasn't too worried. It was a really cold night (in the single digits) and it snowed. I thought she just wanted to stay in the warm and dry. The rest of my girls came out and ate normally. I went back out about two and half hours later to change out their water and check on them and the one was still way back in the hen house. I opened it all up and pulled her out and realized she had some frost on her feathers. One foot didn't want to let go of the roost. I immediately brought her in and put her on a towel in the bathroom. She doesn't seem to have frost bite on her waddle or her comb and her feet felt warm, but she isn't standing up. I soaked her in lukewarm water and that seemed to pep her up a bit and she stood on one foot but is now laying down again. Do you think she has frost bite? I have never encountered this before. We live in Colorado so we get some cold weather but this is about as cold as it ever gets. It was 60 degrees a couple days ago. My worry is that the rest of the flock (there's 4 of them) often leave her out when they huddle at night. Is it possible she just got too cold? Her crop is full as well. Maybe she has something else going on? She seemed very happy yesterday. I'm at a loss and very concerned. These girls are my pets and very loved. Any advice would be great.