I've noticed that my bunny, whenever he hops across my room or something his leg will make this cracking noise. It doesn't seem to cause him any pain but he doesn't do any binkies and he doesnt hop onto my bed or chair like my other bunny normally does. He is quite young, he's only 2 years old so I don't know if it could be arthritis. I was just wondering if anyone else has any idea why he's like this.