You will need:
2 lbs bones (from a whole chicken, turkey, or ham)
2 chicken feet (optional)
3 stalks celery
2 Tbs apple cider vinegar
1 bunch parsley
1 Tbs sea salt
1 tsp pepper
2 cloves garlic
Place all the ingredients in a slow cooker on medium to high heat.
Cook for 2 hours and scoop out any foam that forms.
Reduce heat to low and cook from 24 to 48 hours. This allows time for the vinegar to pull the rich nutrients out of the bone.
Strain. You can then drink the broth on it's own or use it as a base for soup.