My boy stumbled alot when I first got him- usually at a walk. Have been working with the farrier and he has been bringing my guys heels up which has helped a lot. The farrier thinks some of his stumbling was pain from stones, etc since he was so far back on his heels he was getting stone bruises. I also started him on Cortaflex, since he seemed stiff. But sometimes I think he just does not pay attention to where he is going!