Had a customer in Texas that would buy 2 whole chickens and ask us to put them through the meat grinder, bones and all.
Made dog food from it.
That should work.
I had heard you shouldn't let dogs have chicken bones because of the way they splinter. Grinding up the bones probably eliminates that danger.
An old mountain woman friend of my dad had chicken houses way back in the mountains. I helped her in the chicken houses some when I was young. She went through the chicken houses every morning gathering any dead chickens and tossed them to her pack of Bloodhounds that were waiting outside the door.
Like most mountain folk, she didn’t waste anything. I ate lunch at her house one day and she made a chicken stew. I was eating away when a chicken foot floated to the top of my bowl.
I was done. She just laughed when I said I was full.