I noticed one of my wethers was lame, checked his feet which looked fine but I sprayed with Alamycin anyway. He seemed to improve, he no longer lies down a lot but now when he runs he loses control of his back legs. He is in a field with a bunch of youngsters including Soay's who love to run around playing and the ground is uneven and wet so I don't know if he's just injured one leg while they've been playing and he just can't hold himself up properly or if it is something more serious? He seems to walk around fine and always comes for his hay. Checked his feet and legs again and can't see any obvious signs of a problem. From researching online I thought it could be swayback but I'm not sure. Any advice would be much appreciated.