IF USING A COLLECTION OF BONES, SKIP TO STEP 4.Divide the chicken into 9 pieces -- 2 wings, 2 thighs, 2 legs, 2 breasts, 1 back. (If the chicken neck is included, cut or break into several pieces.) Place chicken pieces in a large (6-8 quart) pot with water and salt.
Boil for 30-40 minutes or until chicken is cooked through. Skim off any brown foam from the broth. Transfer chicken to a platter and allow to cool until easy to handle; reserve broth in the pot.
Strip meat from bones and reserve for other recipes. NOTE: I do not recommend using the meat for the stock because the texture becomes dry and mealy when cooked too long and doesn't add to the quality of the stock.
IF USING A COLLECTIONS OF BONES, START HERE: Place bones, celery, carrots, onions, and garlic in a roasting pan with 1/2 cup of water to cover the bottom of the pan. Bake at 400°F for 30-45 minutes or until bones and vegetables are a dark golden brown.
Be sure to check periodically to add a little water to the pan so the bottom does not burn. When the bones are dark golden brown, transfer bones and vegetables to the pot with the broth. Add 1 cup of water to the roasting pan, stirring and scraping to loosen any browned bits.
Pour this roasting liquid into the pot and add the apple cider vinegar and thyme. Fill the pot with enough filtered water to cover the contents plus about 2 inches above. (If starting with just bones, there will not be broth to add water to, just fill the pot with filtered water.)
Bring to a boil. Reduce heat and simmer for 6 to 24 hours (remove any brown foam with a slotted spoon). The longer it simmers, the richer and more flavorful it will become. Add the parsley the last 10 minutes of simmering.
Allow the stock to cool slightly, then strain. Discard solids. Use a separator to remove fat or let cool in the refrigerator and remove the congealed fat that rises to the top. NOTE: I do not recommend using the solids for soups or other recipes when they've been cooked so long due to texture, lack of flavor, and the nutrients have already been released into the stock.
Stock can be stored in the refrigerator for up to 5 days or frozen for later use.
If using a 12-quart stock pot, double the recipe. Any time you have bones leftover from a baked chicken or turkey, freeze them until you are ready to make a stock. It is not necessary to roast the bones and vegetables, but the flavor is well worth it.