I'm interested in this topic, too. My rooster's comb is dry and whitish looking lately. I was hoping it was dust or dirt or dried yogurt, but it won't come off with a warm washcloth. I'm wondering if it's a fungus. If so, I think you can treat it with athlete's foot medicine, but let's all wait to see what more knowledgable folks have to say. I have rubbed his comb with triple antibiotic ointment and it makes it look a little better, but once it wears off, the whitish look is still there.