My cat brought home an alive field mouse. I took it from him and discovered that the mouse is dragging his leg, so I think it is broken. I do not see any blood on him and he is pulling himself around ok. I placed him in a box with alfalfa and hamster food for now. I do not want to leave him outside to die. It is about 35 degrees outside and raining. Is there any chance for this little guy?! What should I do?