Small block dots on combs

[KK'schicks]

Can someone please tell me what these black marks are on the chickens? They will wipe off if I rub hard.
Not sure if it’s fridtbite or possibly fowl pox? They are about 6 months old.
Thank you!!!

 

[WhiteWyan]

I am wondering too! Mine have the same thing. I haven't tried rubbing it off though.

 

[Alaskan]

if it rubs off... without leaving a mark, then it can't be frostbite or fowlpox.

Maybe just dirt?

 

[aart]

Mine get that from time to time...it seems to come and go.
IME it's nothing to worry about, just keep an eye on it.
Best not be rubbing anything hard of you're in frostbite country.