the vet thinks he was stepped on by a cow..... he said he has "barncat" characteristics and he had "cat scratch fever" when i first got him and the worst ear mites and giant fleas... he was not in a good way when i got him.... he cant really jump very high right now - i think it's not a matter of "mobility' but more of a pain thing later on when he gets bigger - he's only 4lbs right now so he doesnt have much to support - it's his left back leg... not a front leg.