I recommend organic chicken for the primary ingredient for this recipe. And, whenever possible, use organic or locally sourced produce for the other ingredients.

Yields: 3 quarts, Prep time: 20 minutes, Cook time: 14 hours 30 minutes

Ingredients:
3 pounds bone-in chicken parts and gizzards
12 cups filtered water
1 tablespoon apple cider vinegar
1 yellow onion, peeled and quartered
3 large carrots, cut into large dice
4 cloves garlic, smashed
2 stalks celery with leaves
2 bay leaves
1 teaspoon sea salt
1/2 teaspoon cracked black pepper
1 bunch fresh parsley

Preparation:

1. Place the water and chicken parts in a slow cooker and cook on high for 2 hours. Skim off any foam from the surface and remove the chicken. Shred the meat off the bones, and set the meat aside. Return the bones to the pot.
2. Reduce slow cooker to low. Add all the remaining ingredients, except the parsley, to the pot and cook on low for 12 hours or on high for 6 hours. Turn off the pot, skim the fat off the top, stir in the parsley, and cover for 30 minutes.
3. Strain the broth through a fine-mesh sieve or cheesecloth. Store in the refrigerator or freezer for later use. Scoop off any solidified fat before using.

Image Attribution: paulista/bigstock.com
Source: Danielle Walker, AgainstAllGrain.com.