My ~30 year old QH gelding is walking weirdly on this back legs. When I lead him forward he wants to face left and seems to side step on his back legs. Its odd I don't know how to describe it well. When he stands he leans heavily on his back right leg. He is not limping, there is no visible injury and both back legs do not feel hot (that I can tell). He's eating and drinking like normal and doesn't react when I touched his legs. He lives in a pasture with three other horses and we think that on of our younger & larger mares, who has picked on him before, may have kicked him but we are not sure. Could this just be a sore/pulled muscle or something worse?