You can use a mix of bones for this - just be sure to use some bones with some meat on them, like our soup bones, neck bones, short ribs, or oxtail.
1.Preheat oven to 425 degrees F.
2. Place the bones in a single layer in a roasting pan and roast for 60 minutes. Flip the bones halfway through.
3. While bones are roasting, chop the vegetables into large chunks and place them with a bay leaf and apple cider vinegar into the slow cooker. Be sure the slow cooker holds 6 - 8 quarts.
4. Add bones to the slow cooker as soon as they are finished in the oven.
5. Fill slow cooker pot completely with water.
6. Set the slow cooker on low, cover and cook for 18 - 36 hours, or until the broth is brown in color and rich in aroma.
7. Remove the bones and large pieces of vegetables from the stock and strain in a colander.
8. Remove from the colander, then strain the broth through a fine mesh sieve.
9. Transfer broth into jars and refrigerate immediately. The fat will float to the surface in the cooling process which can easily be removed and discarded with a spoon or spatula.
**Once the jars are cooled, you can transfer them to the freezer to keep for a later date. Broth keeps for up to 6 months in a standard freezer. Don't place hot jars in a freezer and don't quick thaw glass jars.