I liked your post of cooking down the bone and scrap for preserving for dog food. I didn't think canning broth was really worth while, but this put a new twist on it.
I may be the only person who thought it was worthwhile to do this. All I have to do is look at the ingredients list on the can or box of broth from the store and it becomes worthwhile to me. Three organically raised chickens that were on sale and enough water to keep my water bath canner pot 2/3 full. Plus herbs - I remember adding a bay leaf, basil, parsley, sage, poultry seasoning and peppercorn. I may have added more. I also added chopped carrots, celery, garlic and onion. It takes a lot of cooking to soften the chicken bone so you have to consider whether it's worth the time and electricity to do so. I put my broth on to simmer while I was awake and turned the burner down to low while I was sleeping and it took 24 hours. I poured it through a strainer at about 12 hours cooking and tossed the veggies to the chickens and separated out the meat I was going to can. The bones weren't soft enough at that point. You have to be able to break them easily between your fingers before they are safe to give to dogs. So I put the bones and scrap back in the pot and simmered for another couple of hours. I poured it back through the strainer again and let the bones cool a bit so I could mash them all with my hands then put them back in the broth for the last couple of hours.
I probably shouldn't have done so much taste-testing with the coffee mug. I drank at least a quart of the broth while it was cooking.
I can't find the nutritional details on bone broth website, but when you cook through the marrow of bones you get a lot more minerals and vitamins than just a short cooking of the chicken. The bone broth becomes a whole food at that point and personally, I could live on it in the wintertime.
Last step - I poured everything through a cheesecloth lined strainer. All of the bone, cartilage, skin and gristle went into a 2 quart container for the dog - it didn't fill the container. So, for someone like Jim with his Pomeranian, it might be a week's worth of dog food, but for me with the 140 lb great dane, it's only about a handful a day added as a supplement to dry food for a week. I had enough chicken meat to make 6 quarts of chicken soup base - I filled each quart jar half full of chicken then poured broth over it. Knowing the canner will only hold 7 quart jars, I filled 8 more jars with broth and had enough left over to drink another mug of it, pour some over the dog's food that evening and make a pot of chicken and dumplings.
This is a 50% concentrate of broth, I found. With what I had left over, I added the same amount of water and got a wonderful tasting broth for my Sunday dinner.
The plain broth only took 25 minutes in the canner but the chicken/broth mix took 75 minutes and the first time I did it, the canner ran out of water 2/3 of the way done and I had to let it cool and do it over again with more water added.
This was my first time doing this. There are things I will definitely do differently next time. Like the vegetables will go into the broth in a cheesecloth bag so I don't have to pick them out from the mass of chicken. I think they were necessary to get the final flavor that I'm so pleased with and it's never a waste to make more chicken food from things that grew in your own garden. I will do four or five chickens, depending on size, instead of three so I can get 3 full canning pots of quart jars.
The worst part of every canning experience for me is the cleanup. My kitchen is always a mess afterwards. On the plus side, I won't have to buy chicken for another year now.
That's been the most important thing I've learned this year - I have to really think about how often I'll eat the things I'll can and not make more than that. The other issue that I have is that the high pressure of canning not only destroys bacteria - it also destroys nutrient content. That indoor garden looks more and more attractive every day!