Our lab killed one hen "playing" with it. That's all it took for her to learn her lesson and now she protects the flock at night from all the other critters.
Wingding, as she is now known, is completely recovered and back with the rest of the flock. The only way to tell her apart from the others is that she eats from my hand. And Eugene the shelter dog is thriving at my dad's house! Thanks for everyone's help!
It was a recently adopted shelter dog. He's already been rehomed to my father's house with nothing he can hurt. She seems to be feeling better! She's eating and no longer has the shocky look in her eyes!
She seems to be exhausted and in shock to me, but I wouldn't say suffering. She walked away from the attack, but not interested in food or water. It looks like he plucked her pretty bad,but no obvious muscle injuries.