I've noticed for the past couple days that DD's rabbit is not putting any weight on her right hind leg as she hops around. I don't know what happened, and the kids say they don't know what happened. I've shown them how to handle rabbits gently, and every time I see them with the rabbits (even if they don't know I'm watching them) they've been very gentle. Poor thing, I'm feeling badly for her. How do I found out what's wrong without making an expensive trip to the vet?