Has anyone tested him for Lyme’s disease? Just a thought. Seems though Lyme’s is getting more and more prevalent in horses. Also, homeopath is another good option. My QH had a bad limp for about a year, and had homeopath out and he did chiropractics and gave him some meds for liver support and voila, he’s all better! 🙂 Oh, and he did test negative for lymes at that point.