fungus?

[mtn_bob]

3 year old barred rock, never seen this on any others.

 

[mtn_bob]

Should have added, she's the alpha hen, so not being pecked.

 

[dawg53]

I suspect that it's either scaly face mites or favus, maybe both. Fowl pox crossed my mind but I doubt it.
The good news is that you can treat both favus and scaly face mites at the same time but requires different treatments, both take time to heal.
Both favus and scaly face mites are contagious to other birds, favus can be transmitted to humans because it is a fungus.

Treatment for favus is miconazole cream. Wear disposable gloves and apply the cream on affected areas until completely gone.

Ivermectin will treat scaly face mites. Here's a link for you to read about scaly face mites.
https://wagwalking.com/bird/condition/scaly-face-mites

 

[mtn_bob]

Thanks, will give it a shot.