Roosters with black spot on comb

[MapleFrontFarms]

I have three roosters, one australorp, one buckeye and one campine mix. They will be a year old in the spring. They were brought to me about a week ago. I have no other birds. But these three all have black patches on their combs. I'm not sure if it is pox, or if it is frost bite? I live in Nova Scotia, Canada and temperatures here hover around -15 degrees Celsius. They are in a protected coop here, but I don't know what their coop was like where they came from. They all behave regularly and are very sweet boys, they don't have any other issues.

If it is pox it will simply pass, if it is frost bite it should heal, correct?

Here is a picture

 

[Granny Hatchet]

looks like very mild frost bite to me but i dont know what pox is. all my roos have this now. very harsh winter here. it will heal on its own. nothing to do after it happens, just prevention before hand.

 

[Sagetown]

looks like very mild frost bite to me but i dont know what pox is. all my roos have this now. very harsh winter here. it will heal on its own. nothing to do after it happens, just prevention before hand.

Yep; that was my thought as soon as I saw it. Frostbite.

 

[hmoran]

yep, frost bite, most likely