If your chicken has frostbite, then that means your coop is to cold with to much condensation. The way to fix that is to winterize your coop, that's what I did when I saw my Rooster with frostbiten comb tips. So I got some plastic wrapped it around my coop but I left some parts uncovered so the condensation was out but so was the wind. Only leave patches of no plastic at high places twards the top of the coop. If your coop is covered then that means your chicken is not cold hardy, and I usually don't recommend this but maybe an added heat source would be a good idea. Just be very careful because of coop fires. If you are wondering what will happen to your chicken after frostbite, what will happen is the parts that are frostbiten will fall off, and sadly will never grow back. If you aren't sure what frostbite looks like then it is eather white black or grey and usually starts at the tips of the combs. Like in the picture at the bottom of the page.
Hope this helped you, and I hope you liked it!