Add all ingredients to a 6 quart (or larger) slow cooker.
Lid and cook on low simmer for 8 to 10 hours. The longer the cook, the more bitter the broth so start with a shorter time to learn taste preference.
Allow the broth to cool a bit so that nutrients on the lid condensate drop back into the broth.
Unlid the pot by opening it away from you to prevent burn from escaping steam.
Using a slotted spoon or tongs, remove the large pieces from the broth and plate them in a rimmed bowl.
To remove the remaining solids, use a ladle (or 2 cup glass measuring cup) to dip into the broth and pour it through a stainless-steel fine mesh strainer that has been placed over a large stainless-steel stockpot. Preferably do not use a plastic strainer as the heat of the broth could leach chemicals from the plastic into the broth.
Allow the broth to cool. Then lid it and place it in the refrigerator overnight until completely chilled.
The fat will solidify on the top surface. I always recommend to skim off this fat (even pasture raised chickens) because contaminants in the soil has been mentioned in the literature and those could be stored in the fat for pastured chickens. You can choose to leave the fat if you are certain the bones used are of high quality. Step 11 describes how to remove the fat from warm broth.
Concerning the solids removed from the hot broth, once they are cooled enough to handle, use your fingers to separate the bones and undissolved gelatin from the plated cooked vegetable mixture. Save the bones and undissolved gelatin as these can be reused one more time to repeat the entire process (or they can be frozen) for a second batch of broth. Toss the cooked vegetables after each batch. Toss the bones after the second batch. When making batches back to back, I combine both batches of bone broth in a very large stainless-steel pot and refrigerate overnight. Fat can then be removed as described in step 8.
To store Bone Broth: Bone Broth can be refrigerated for 4 to 5 days. Alternatively, freeze Bone Broth for extended storage in convenient sizes. A repurposed 20 oz. glass food jar is perfect. Fill glass jars just under the bend of the jar (and at least an inch below the top of the jar) so that it doesn’t break upon expansion from freezing. Ice cube sized portions are also convenient for some recipes. For a fat-free broth, use one of these methods:Method 1: Allow the broth to cool. Then lid it and place it in the refrigerator overnight until completely chilled. The fat will solidify on the top surface which can then be scraped off and discarded.Method 2: While the broth is still warm, pour it into a glass grease separator (available at Amazon or kitchen stores). The separator allows you to pour the fat-free broth from the bottom. Preferably, do not use a plastic fat separator as the heat of the bone broth could leach plastic chemicals into the broth.