I have a male guinea pig almost 2 years old who has sudden unexplained hair loss right above his testicles. He is on a vitamin C supplement from oxbow and gets daily fresh veggies so I don't think its scurvy. It is also not another guinea pig he is housed alone( he is extremely aggressive with other guinea pigs he has drawn blood on many of them during introduction.) He is housed next to another guinea pig I adopted who needed to be housed alone but the cant get at each other. The hair loss was very sudden over no more than 2 days. The area of hair loss is not crusty red or painful So I don't think it is a parasite or infection. The only thing I could think of is that it may be hormonal it almost looks like what happens when female guinea pigs get ovarian cysts. But again he is a male so I'm kind of at a loss. Dose anyone have any ideas