I'm think I may have been sold miss sexed guinea pigs. I was after a couple of girls but I've noticed this morning that one of them has spent pretty much the whole morning trying to mount the other. I've looked myself but I can't be sure although I think there may be a slight difference with their bits and pieces. How obvious would it be? Also if one does turn out to be a boy what sort of price would it be to have hin neutered?