Would agree with the others, we had one (light sussex) attacked by a fox resulting in a large puncture wound on her back. We sprayed with the sheeps purple spray (it was the only thing to hand at the time), and kept her separate for a time. She was very quiet, but would say she was bound to be - think we'd all be a bit under the weather with a large hole in our back - but is now recovered and laying well. She did suffer from feather pecking when she was returned to the 'flock' (2!), so you might want to watch for that. Not sure whether it was malicious or the other hens trying to clean her, but it did keep making her bleed so it was a bit of a concern.
Purple spray took months to come off though!!