Rooster combs turned black

[carla reed]

I have 2 roosters. Live in Arkansas the temperature got down in the single digits now my roosters combs are completely black. Whats the cause & will it hurt them

 

[Rose Quartz]

Most likely frost bite, yes it's painful for them.

Solution so it doesnt happen again is either better ventilation, or less draft. Which can be frustrating to figure out.

Generally if you go in the coop and you can feel a breeze where they'd be sleeping at night, you need to add something to keep the wind from hitting them directly.

If there doesnt seem to be a draft then it's likely moisture build up from their breath and droppings near their heads, which is why they'd need more ventilation, higher up from their roost, but not going to blow right on them when the wind picks up.

 

[aart]

I have 2 roosters. Live in Arkansas the temperature got down in the single digits now my roosters combs are completely black. Whats the cause & will it hurt them

Can you post pics @carla reed ?
Likely they will heal up just fine on their own, but it will take a couple-few months.
Best not to treat or touch at all.
Here's what the progression looks like:
https://www.backyardchickens.com/articles/frostbite-in-sw-michigan.74597/