It is goats mating season starting now rosco will probably stink really badly too as males pee on themselves to impress the girls he will also be protective so watch yourself.
A good website to get info about goats is www.fiascofarm.com
Looks like he got in a fight with another roo and got the worst of it. I would disinfect it and put some sort of cream on it and let him bsck with the rest just wstch it doesnt become infected