Best way to prevent frost bite is to stay out of the wind, sub freezing temps, and not get wet.
Oils and such won’t protect against frost bite, as it is the freezing temps that cause the skin to freeze. Oils won’t protect skin from freezing. Damage from frost hit will take up to a couple weeks to become apparent. Skin will slowly blacken as it dies off, the blackened skin. This is actually necrotic tissue that has died. If the tissue death is extensive infections can set in and sepsis can kill.
Animals like poultry are highly susceptible to frost bite due to their exposed skin, even those with small combs and wattles can get frosted, and legs and feet are also extremely prone to this.
And this is why I do not let my chooks out in the snow, if their feet get wet then they are prone to freezing, better safe than sorry I say. Winter will eventually end, and good weather will arrive - then the chooks can all enjoy the bugs and green grass.
If your chooks get frosted combs there is nothing that can be done other than to keep them in a draft free space, and give pain meds - trust me even minor frost bite is very painful

. Tylenol would be fine, I would stay away from aspirin incase the skin starts to bleed.
If the other chooks start to pick at the necrotic skin you will need to keep the animal separate from them until it heals fully. Never ever rub anything on necrotic tissue - keep it dry so it eventually shrivels and falls off.
If you suspect any of your chooks have possible frost bite bring them in a warm location to thaw out slowly, watch for pain and give some Tylenol if so.
If legs are affected then my suggestion is to get vet assistance. Prognosis is extremely poor with legs.
Prevention is always better then cure, once that tissue is dead it’s not growing back.
FYI- same deal with people, if your fingers or toes, nose ears cheeks get frost bite, do not soak in warm water or rub, go into a warm dry location and you can gently warm up by laying you frosted fingers on you belly to warm up, or place a warm hand gently over your ears, nose, cheeks or toes. Never ever rub.
Take some Tylenol for any pain, and see your dr or go to emerg for any required treatment. Especially if you are diabetic - I cannot stress this enough.
Ok enough talk of cold, warm thoughts everyone.