Thoroughly rinse all of the bones in the sink, as well as your vegetables. Tie the rosemary and thyme sprigs together with butcher's twine.
Add the chicken bones to the water in your stockpot and bring to a simmer for 30 minutes. Skim off any fat and impurities that rise to the surface. Add the remaining ingredients, cover, and simmer on low for 5 hours.
Strain through a fine-mesh sieve into a heat-proof container. Discard solids. Place stock in the sink with enough ice around its container to cool it down. Using your fat skimmer, remove any fat that rises to the surface and discard it.
Ladle the stock into 3-4 cup freezer-safe containers. The stock will keep up to 6 months in the freezer.
Note that no salt has been added to this recipe, unlike the stock that you would find on a grocery store aisle.When using it with a recipe that calls for chicken stock, add 1/2 teaspoon kosher salt per quart (4 cups).