I've been collecting chicken bones from both legs and thighs - both after being cooked or when I debone the thighs before cooking. I have been putting them in a Ziploc in the freezer and finally got a full enough bag to make some bone broth.
The house smelled so good, but the best part was straining the broth and a sample taste to make sure it was seasoned correctly. OOOOHHH! Every time I make some of this, I can't help but to think back to my grandmother's chicken soup. She made the most yummy soup with celery, onions and carrots and poured it over her homemade Lane Kluski (Polish poured noodles). I never learned how to make it the way she did, but my broth is about as close as I'm probably ever going to get.
After straining and cooling the broth, I put it to chill and will remove the fat layer that forms on the top. My broth will be quite like jello and will need to be reheated to either can or make chicken soup with. I haven't decided what to do with it yet. Everyone here is now begging for soup since it smelled so good when it was cooking.
The bones were soft and easy to break, so they were broken up in small pieces to add to the compost - not exactly bone meal, but will easily break down since they are broken up into pieces. These will help increase the calcium and give other nutrients to the garden. The rest of the veggies that didn't go in the cat food also went into the compost. Nothing was wasted except for the skin and the fat from the raw chicken. I didn't use that but should probably look up how to use that as well so I don't waste anything from the chicken.
Chicken thighs run $0.99 a pound here. I bought a 3.81 pound package and after removing the skin, most of the fat and bone, I ended up with 2.25 pounds of chicken. I had about $1.25 of waste. By making the broth and kitty food plus the bone "meal", that waste which normally would have been thrown out, became something delicious and useful (except for the skin and fat, that is).