I noticed one of my buff orpingtons has been hanging out in the nest boxes a lot this week. This is pretty common here as my buffs seem determined to hatch some babies. Anyhow today she was on the edge of the box when I noticed she's missing two nails. Two days ago I saw one tiny spot of blood on my bottom roost, but didn't see any blood on my chickens so I didn't panic. I obviously didn't do a very thorough check or I would have seen the toes, but that was the only spot I ever saw. The two missing nail spots are not bleeding and don't look swollen/infected, but the third nail looks dark reddish black. Could this be from frostbite? We did have a really harsh winter (as most of the US) this year, but I kept a heat lamp hooked up to a thermometer to keep the coop at 40 degrees average. I do open the door just about every day. The only days I did not was when the temperatures were in the negatives. They don't really venture out on cold days anyhow. Is there something I can do to save the last nail? I offered food and she'll eat it and she seems perky otherwise. Now that the snow is melting it's pretty muddy and I have one last question. Should I cover it somehow to keep the mud out? Any advice would be greatly appreciated.