I have a 3 year old golden retriever who seems to be in fine health. He runs with me every day and eats well. For the last few days I've seen him having a bit of trouble standing.. he seems to twitch a bit, or maybe stumble, but then be fine. I've also seen him twitch a couple times while just laying on the ground. I doubt its dysplasia, because I had his hips x-rayed before and they look fine. Anyone have any ideas?