I agree. Jaw problems a sign of more severe MBD; there would be other symptoms. If there are no other symptoms, I'd bet it's a URI or possibly a bit of shed stuck in his nose (I know it sounds weird, but it can make a very strange clicking/whistling noise!).pscaulkins":346l0jdh said:Jack are you sure the sound is coming from the jaw and not breathing? The reason I ask this is once when Semi had a RI, I heard clicking and thought it was his jaw when it was really his breathing occasionally. I really don't know if jaw clicking is MBD. Are there other symptoms of MBD present?