Spots on comb look like a bit of dry pox, virus spread by mosquitos.
Best left alone, it'll go away within a few weeks.
More pics of barn, inside and out?
Looks like eaves are closed off?
Which is too bad because that's the best place to ventilate on cold climates.
Temp and humidity should be about the same inside and outside building,
with a bit of lag throughout the day/night,
that's when you have enough ventilation.
It's the near freezing temps surrounding thaws when I see the most frostbite.
Gray is mild, white is serious, black is severe(necrotic).
Hand off here, before and
especially after, all have healed.
https://www.backyardchickens.com/articles/frostbite-in-sw-michigan.74597/