Take roughly 2 pounds of bones (I use beef and lamb) and place them on a baking sheet. Bake on 350 for about 30 minutes. Remove from baking pan and place in crock pot or in stock pot. Pour about 1/2 cup of apple cider vinegar over the bones. Turn on the heat to high. Pour 2 gallons of filtered or spring water over the bones. Bring to a boil then turn down to a simmer.
If using a crock pot you can turn it up to high then turn it down to low after the heat has risen all the way. If using a stock pot just turn to the lowest setting once you have brought the liquid to a boil. You’ll want to scoop the foam off of the top periodically. This usually appears in the first hour. The higher quality diet of the animal, the less the foam will occur. I have let the bones cook for 12 hours but now I like to cook them for 48 hours. Towards the end you can add in any vegetables or herbs that you like. I have been leaving my broth plain because I like to use it for cooking and drinking. I add salt to taste as I use it in other recipes or as I drink it. Let cool. Scoop the fat off the top and package up for the freezer or refrigerator. I have not yet canned my broth but I want to do this soon since I make so much of it. I tend to keep the broth in half gallon plastic containers (not ideal) and put them in the freezer. I take one out at a time and let it thaw in the refrigerator and use it over the span of a week or so.