The difference between bone broth and meat broth, is that the bone broth needs to be cooked longer to extract the nutrients from the bones. While meat broth can be boiled for only a few hours, bone broth should be boiled for at least 12 hours (though I have boiled it for less in a pinch). Bones and marrow are richer in nutrients than just meat, and for Ellie I make sure and boil a piece of meat in with the bone broth to add more variety of nutrients and then have something to make puree (or pate') out of when it is done.
If you are not happy with the density of the broth when you are done, you can take off the lid and continue to cook it down until it is more condensed. The thicker, or denser in color, the better the broth. Also, if you are going to make bone broth with something other than a bird that will easily come apart, you need to make sure that the bones are not whole and the marrow is exposed. Adding pork skin or poultry skin into the broth will add additional nutrition.
It is abest to use grass-fed, organic meats and bones. If you use regular commercial meats you will be extracting the anti-biotic residue, chemicals, and other various things that will not be conducive to healing!
To make the broth:
Defrost the bones and meat. Place them in a large pot and cover with COLD water. Add a handful of coarsely chopped peppercorns. Peppercorns add other nutrients supposedly, but I don't know what those are!
Place the pot on the stove without a lid and bring to a boil. Skim the foamy funk off the top and discard. Do not remove the fat. Not now, and not at the end. The animal fat is super nutritious and good for you! (And once you add vegetables in to make a soup, it is much less noticeable.)
Add sea salt 'to taste'.
Reduce the pot to a low rolling simmer/boil, and put on the lid. Cook for as long as you can! (but not more than 24 hours)
When the broth has finished, it is easiest to strain it right away. If you let it cool then you have to deal with the solidifying fats and meats left in the pot. Use a fine mesh strainer and pour your broth through it. Discard the funk in the trash. Separate out the bones, and knock the marrow out on a cutting board if it has not cooked out into the broth already. It is a goopy gelatinous stuff that is not very appetizing in appearance. Don't let preconceived ideas turn you off to it's value!
At this point you can put the meat in the fridge to add to the broth later and make soup, or freeze it, or puree it, or combine the bone marrow and the meat together and blend it up. There are lots of options.
Use the broth as a warm drink, cold drink (?), use to make soup, or to cook with. Keep some in your freezer for help battling viruses and colds.