Is it an infection?

[jasloz]

I have a Japanese quail that's about eight months old (male). I recently noticed that his vent is red and really swollen. It even looks like he's missing feathers. I'm not really sure what to do about it, so I have him separate from the other quail for the time being. Can anyone tell me what's wrong with him?

 

[DK newbie]

Does sound like some kind of infection, but whether it's parasites, bacteria or fungus - maybe even a virus - I can't tell.
I'd give him the full course of probiotics, grapefruit seed extract, apple cider vinegar, perhaps apply some antibiotic ointment - whatever you have on hand that might be beneficial and is unlikely to harm him.
Usually vent issues are a female-thing related to egg laying, I'm not sure I've ever head of a roo with vent issues. So I'm thinking it's most likely caused by something in his gut that causes his feces to stick to the feathers or annoy the skin and the missing feathers might have been pulled out by himself.
It might be something that cures itself or it could be more serious - if you like your roo, you can try the things above - and keep him warm. As long as his behavior is as usual, he has a good chance.