I have a fifteen year old stallion that, like a lot of stallions, paces the fence. I put him out one afternoon and when I went to put him up he was lame, extremely lame. Couldn't stand to put his left front on the ground and was litterly hoping on three legs. I called the farrier and he checked for gravel or abcesses, punture ect, but there was nothing. While working on him he expressed that he had a little thrush so we poured Coppertox in the hoof and I held it a min or so then put in down. When he put a little weight on it the Coppertox ran out the crack, horizontally across the hoof about 1/2 inch below the coronet band, starting on both heels, towards the front and lacking 1 1/2 to two inches of completly incircling the hoof. I have left him unshod for over a year, with very limited exercise. His hoof has completly grown out but he is still lame on that foot. Has anyone ever had this happen? What caused this and can I get my horse sound again?