Ingredients

3 ½ lbs. chicken parts with bones, such as backs, legs, wings, feet, carcass or one 3-4 lb. whole chicken, cut up and trimmed of fat.
1 large onion, quartered
1 large carrot, cut into chunks
3 ribs celery, cut into chunks
8 sprigs fresh flat leaf parsley with stems
1 Tbs. apple cider vinegar
A few black peppercorns or a few grinds of black pepper
Salt, to taste (optional)
Directions

1. Combine all ingredients, except salt, in the slow cooker. Add cold water to cover by 2-3 inches. Cover and cook on High for one hour.

2. Skim off any surface foam with a large spoon. Cover and turn the slow cooker to low.  Cook for 6-16 hours. If the water cooks down below the ingredients, add a bit more boiling water.

3. Uncover and let cool to lukewarm. Set a large colander lined with cheesecloth over a large bowl and pour the broth through to strain. Press on the vegetables to extract all the liquid. Discard the vegetables, skin and the bones. You can reserve the meat for soup or another dish. Taste the broth and season with salt. Or, wait to add the salt until you use the broth.

4. Refrigerate the broth until the fat rises to the top and congeals. Skim off the fat. The stock can be refrigerated for 2-3 days or can be frozen. I find it convenient to store the broth in wide mouth mason jars. When freezing, leave 2 inches at the top of the container to allow for expansion.  Whether refrigerated or frozen, make sure the broth is brought to a boil when using it.