My dog reluctantly is on a tie out, and gets up and down the steps and a small area to do it's business, and bark at passing dogs. It was very chicken unfriendly as a pup/young adult, it is getting to 3 now, and as long as the bird doesn't flap or run it ignores them, but it knows the taste of fresh meat, so I really don't trust it. Chickens are unbelievably stupid, so unless the dog is muzzled they won't last long. Mine isn't, so I have to keep a watchful eye.
Sorry to be contentious, I realise many back yarders are keeping pets and get all fluffy about them, I enjoy the challenges of rearing them, go ahh when I have succeeded with one of my cross breeding incubator projects and a fluff ball emerges, and harvesting the eggs for sale to the neighbourhood but if it is in distress from an illness, or injured and unlikely to recover it goes to birdy heaven. x-rays, vets.... sheesh.
I don't like it, but we have to manage our flocks.
Just read the good news about bird recovering. Great stuff. From experience if badly bitten or damaged by accident or what ever you usually know straight away if they are gonners, they give up straight away, go into shock, the head goes back and all floppy, and within minutes generally speaking they die. I have tried keeping warm, drip feeding water, and nursing them, but nearly always it is a lost cause.