Add all ingredients to the Slow Cooker and add enough water so that everything is covered, and your slow cooker is about three quarters full, or to the max fill line (amount will vary depending on the size of your slow cooker)
Turn slow cooker on low and cook for a minimum of 6 hours, up to 24 hours. The long cooking time gives the broth a much richer flavor
Throughout the cooking process, because of the long cooking time some of the water may evaporate. You may wish to add a little bit more water halfway through. However this step is optional
When the broth is finishes cooking, place a fine mesh strainer over a large pot
With a slotted spoon remove the chicken bones, feet if you've added them, onions, garlic, carrots, and celery. Place them it the fine mesh strainer to allow any excess liquid to drip off into your pot. They can now be composted
Once all the chicken bones, feet, and vegetables have been removed, ladle the broth into the pot, still using the fine mesh strainer to catch any smaller pieces
When the broth has cooled to room temperature, either ladle it into mason jars (see notes), or plastic containers (such as old yogurt containers)