We use the bones and trimmings from our deer each year to make a big batch (or 3) of broth. We start by roasting everything on the grill outside until the outsides are nice and crispy, then it goes in the stock pot for 8-12 hours to simmer. For the last 90 min we add parsnips, onions (peel and all), celery, garlic and spices. Once it's done we take it off the heat and let it cool so that the far congeals and it can be skimmed off. Then the broth gets canned or frozen and all the bones, scraps and bits of meat and veggies go to the chickens, who devour it all.
Some tricks we use to get a nice rich broth is to save all the scraps that aren't pure fat or bloodshot. All the cartilage, tendons and bits of meat that don't go in the stew meat pile all really improve the broth. Second, we cut the bones in half to let the marrow out easier. Used to do it with a bone handsaw, but we save a bunch of bones so now we just use a reciprocating saw that's cleaned really well after.
