Possible fungal infection?

[GranWin]

Hello!! Our hen started developing a gray spot on her comb a few days ago. Doing some research, it seemed as though she had a fungal infection that I read could be treated with over the counter anti fungal cream. Now the spot is turning black. They have not left their coop during this cold northern MN winter. We leave the door open but they only ever poke their heads out so I don't believe it's frost bite, but I could be wrong. I just wanted to get a second opinion on this. It seems like she might have some nasal discharge and then I was noticing her vent seemed redder than usual as well. She is still laying and her behavior seems fine. I appreciate any help!

 

[DobieLover]

It looks like frostbite.
That in combination with nasal discharge makes me wonder about your coop ventilation.
Do you have pictures of your coop?

 

[MissChick@dee]

Sorry for your troubles.
I agree with @DobieLover it looks like frostbite. The chickens poking their heads out the coop door would not cause frostbite. It’s usually moisture in your coop. Heck some birds can get frostbite from the moisture of tucking their heads under their wing at night. Good news you don’t need to treat frostbite. It’s best IMHO to simply leave it alone.
Where on your hens body is picture #4?
If you post pictures of your coop perhaps we could give some suggestions.

 

[Eggcessive]

Is that her vent in the last photo? What is that sticking out of her vent?

I agree there is a little frostbite on the comb. Didn’t MN have 30 below weather last week?

 

[Saaniya]

Hello!! Our hen started developing a gray spot on her comb a few days ago. Doing some research, it seemed as though she had a fungal infection that I read could be treated with over the counter anti fungal cream. Now the spot is turning black. They have not left their coop during this cold northern MN winter. We leave the door open but they only ever poke their heads out so I don't believe it's frost bite, but I could be wrong. I just wanted to get a second opinion on this. It seems like she might have some nasal discharge and then I was noticing her vent seemed redder than usual as well. She is still laying and her behavior seems fine. I appreciate any help!

It's frostbite
And if there's Respiratory symptoms I will treat and clean her vent too