Well, since she's adapted to her footless life then I'd recommend keeping an eye out for infection on her stumps, and make sure she is not being bullied by others in her flock. Your main concern in this approach is to make sure frostbite does not take the rest of her legs. She needs to be kept clean, dry, and out of the mud. Butterfly would be a great therapy chicken (if she were tame!) as I like to use animals with these challenges to teach kids how adaptable the physically challenged really are.