I've read you can put Vaseline on combs and wattles to prevent frostbite damage. Has anyone tried this? Did it help? Any problems with other chickens pecking at the Vaseline?
It depends how low the temperature goes. Vaseline freezes at -49F, but I have my doubts it's all that effective above that, either. It doesn't hurt to try.
It would protect the comb from moisture from water vapor forming on the comb and freezing. But if it's very much below freezing, your rooster could still be vulnerable. What kind of temps are you expecting?
There really isn't too much chance the hens will nibble it all off the comb unless you leave huge gobs on it.