If you think about it, vaseline could not have much in the way of insulating properties. Think about a mitten, and how it keeps us warm. Vaseline is not much like that. But perhaps it prevents drying after frostbite. There are websites on this issue and human frostbite. Someone studied it and vaseline or something like it did not work. But i have used it on roosters' combs and it seems to make them look better and cleans them up well. Also: I faced the rooster wattle frostbite issue bigtime the last two years. I took him to the vet once. The vet helped me see that the damage was just superficial and convinced me that cutting off combs and wattles to prevent frostbite was an unnecessary and dangerous practice. What I did this year that helped is have enough birds to keep each other warm and insulate my coop.
