Now, we have too many chickens for this to be practical, but they seem to be fine as long as they have protection from the elements and (of course) lots of food.
The two body parts that are most vulnerable to frost bite on a chicken are the comb and the feet. We protect their feet by giving them a thick layer of dry hay to scratch and lie in. As for the combs, well, roosters have one of two types of comb. Some have tall combs that are really easily frozen and some have short, wide combs that are less susceptible. We only keep the roosters with the short combs for breeding.
|A rooster with a short comb (but some frost damage on his feet)|