Put chicken bones and apple cider vinegar into slow cooker.
Cover with filtered water until there is one inch less from the top.
Put on low and simmer for 20-22 hours.
Mixture should reduce quite a bit. Add in remaining ingredients and continue to cook for another 2-4 hours.
After the time is up, filter mixture through mesh strainer or cheese cloth, into a heatsafe bowl.
Cover with plastic wrap and chill.
After mixture is completely cool, you'll notice it solidifying on the top. Remove the fatty layer that settles on top with a spoon and continue to cool.
Store in the refrigerator for up to 3 days or freeze immediately for up to 6 months.