Combine all ingredients in slow cooker and set on low temp and set timer for 12+ hours.
Once cooking is completed, allow to cool and if desired, carefully pick out vegetables and set aside for making a puree to add back to the broth later.
Position a large strainer over a large bowl and pour liquid through the strainer. You may want to spoon out the larger chicken bones first and set aside before straining but it's up to you (and depends on how large your strainer is).
If adding the veggies back to the broth, add the veggies and some of the broth (whatever will fit) to the blender and blend on high speed. Add veggie/broth mixture back to whatever broth didn't make it into the blender and stir together.
Pour broth/soup into large mason jars and store in the refrigerator for 3-4 days or in the freezer for up to 3 months.