First, brooder problems happen. Determining the problem and fixing it is important to success. The Cornish are essentially race cars, fill them with what ever gas, park them on the
lawn and don't change the oil and they will fail. Plain as that.
Second, they don't have many feathers to begin with. If your birds are gashing each other I would recommend increasing feeder space. 4" per bird. They're little fatties and they need some space.
As for feeding scarred birds to the dogs, I say Why!?! I'm sure you've put a lot of time and effort, not to mention money into those birds. That's some expensive $$ dog food! Learn how to bone out a
chicken, and do that when you process. A scarred back doesn't look nice, but those breasts, (boneless, skinless or bone in) are still good. Not to mention wings, legs and thighs, necks, backs, and giblets for making stock! Then feed the rest to the dogs.
If you've got a dog that goes after
chickens, you have a dog that goes after chickens...not a guard dog. Electric
fence helps. Harsh maybe... but my dog knows it and stays away. That being said, the presence of any dog deters predators.
Grind up the carcasses and feed a raw chicken mush. This really isn't necessary, but my dog for example is far less inclined to bury the mush in my garden for a later snack, than she is to bury a carcass. The only concern I'd say is if you've never fed
raw food before it may cause an upset stomach. Just feed sparingly I guess. Also, the raw bones are safe. Cooked, not so much unless you cook them till soft in which case I'd make sure the dog gets the broth too. Don't want to waste all the good nutrients. I've seen the ground carcasses baked into chicken cookies for dogs too.
If you take your birds to a USDA plant rather than processing them yourself, the inspector will make the call on weather its good to eat. You may get some birds back with one wing, no wings, legs missing, whatever. The rest is good. I assure you.
I have spent the last 5 years involved with and currently in charge of raising, processing, packaging, marketing, and selling anywhere between 9,000 and 14,000 broilers, with live stock guarding dogs fed solely a raw diet of mostly chicken(parts, organs, carcasses, and ground).
To sum it up, process and save what you can, feed the scraps to the dog. I realize I'm a bit late on this post. I work a lot and don't get on here much. :-/ I hope this helps.