just as important as heat is proper ventilation, not drafty but circulating air, humidity is what will cause frost bite and to prevent it you need good air circulation away from where your chickens roost, somebody wrote a really good page about it someplace on this forum about this but i don't know who or where. unfortunately for you and your chickens it does sound like frostbite, depending on how far it has spread parts of the waddle may need to be removed to prevent infection [i think, don't hold me to that]. vaseline does help, around here people put it on if it drops below 10, but its really only necessary below zero, it helps if you run the container under warm water for a couple minutes to loosen it up before applying it. basicaly all the petroleum jelly does is keep all the water and moister off the flesh.
