I have a Cayuga duck I got as a duckling from the feed store this year, and he's been having fits of some kind. When he was a few weeks old, he would suddenly shriek and pull his head back and fall over on his back and paddle his feet. After a minute he'd just be a little woozy, but then he'd be walking around like normal soon after. I had quarantined him, just in case, but he seemed fine except for his occasional fits. This stopped at around six weeks or so, and he didn't have problems until recently(he's about twelve weeks now.) He had been vigorously flapping his wings for awhile, and afterward he was really woozy and off-balance. He staggered around for a little bit until I supported him, and after half a minute he was back to normal. I don't believe it's anything serious, since he's in good health otherwise, but I wanted to know if anyone had any ideas about what his problem is.