Place the 20 ounces chicken bones, 1 onion, 2 carrots, 2 celery stalks , 4 cloves garlic, 1 lemon, 2 bay leaves, 1 tsp peppercorns, and 1 bunch parsley, into a pot.
Pour in 8 cups water or enough to cover everything by about 1 inch.
Bring to a boil, then immediately reduce to a low simmer. Skim any foam that rises. Let it simmer uncovered for 2 -3 hours.
Remove large bones with tongs, then pour the broth through a fine strainer into a heat-safe bowl or jar. Add salt to taste only after straining. Cool completely. Refrigerate up to 5 days, or freeze up to 3 months.