Nella,
I hope your Hen does Ok. I have a Hen in the house right now recovering from a Dog attack. It's my next door neighbors too, my In-laws. They feel awful and want to pay for me to take her to a vet, but I've told them there isn't a chicken vet.
She has some similar injuries to your Hen, her left leg is injured, but with no signs of a break. She just won't bear weight on it. She has lost a LOT of feathers, mostly on her chest and legs. She does have some broken skin, but no puncture wounds. I believe that is because my in-laws dog is a retriever and her chosen method is to catch and shake, not rip and tear. Most of her broken skin is from small abrasions in the skin, tares from rough treatment.
What we did, was first place her into a bird cage with some brooding chicks we had that were going out to a friend the next day. It had a warm light on it, and only 4 day olds in it. We then changed the water from plain water to water with Vitamins and Electrolytes added. This can help both the newly hatched chicks and the hen who has been through a trauma to recover from all the effort put out in both situations. You can get the bag of vit and elec. solution at your feed store.
I also picked up some unreconstituted antibiotics just in case I noticed any signs of infection. I wasn't sure I'd be giving it to her because her wounds were clean. With puncture wounds I would have grabbed the penicillin.
We are trying to keep her quiet, clean and keep the light dark cycle of the lights as close to normal as possible. We're giving her water, crumbles, greens (she's free range normally) grit because she can't get it on her own in a cage, and oyster shell because she needs extra calcium to help her recover from an injury.
Laney