The neighbours cat caught two mice this morning, the adult was already dead but the younger one survived. He's about half the size of the adult and has fur. He was moving around and tried climbing the walls of the cage but was dragging one of his back legs behind him, there's no blood but I think it might be broken? I would take him to my local wildlife rescue centre but they're full so are not taking any more phone calls or animals! What should I do? Will he survive if I let him go? Or should I keep him until his leg gets better?