In a 3-gallon stockpot, combine all ingredients and fill with enough cold water to cover ingredients by 3 inches when submerged (about 6 quarts).
Bring to a rapid simmer over high (do not boil); reduce heat until bubbles barely break the surface. Simmer until flavorful, about 2 hours, skimming stock with a ladle every 30 minutes.
Strain stock through a fine-mesh sieve. Discard vegetables. Remove meat from bones and save for another use; discard bones. Let stock cool completely before refrigerating.
Keep the stock at a bare simmer; a hard boil would evaporate too much liquid and make the stock cloudy. Any fat that remains after skimming can be easily removed once the stock is chilled. If you don't have a large stockpot, use two smaller pots.