1. Preheat oven to 400º
2. Place the duck carcass and neck bone in an oven-safe pan. Roast for 20-25 minutes or until bones are dark but not burned. (This process will bring about a delightful smoky flavor to the stock)
3. Remove from oven and allow to cool. Then place contents into a 6 quart stock pot. Add enough water to cover contents completely
4. Add carrots, celery and onions (mirepoix)
5. Add bay leaf, whole peppercorns and thyme sprigs
6. Bring to a boil uncovered. Then simmer uncovered, over medium-low heat, for about 3-4 hours
7. Drain and strain liquid and allow to cool slightly, then refrigerate
8. Skim the layer of fat that forms on the surface and the stock is ready to use

Tip: Duck stock freezes well. After straining and completely cooling the stock, pour into an ice cube tray and freeze until solid. Then transfer cubes to a freezer bag (don't leave in ice cube trays because it will pick up odors from the freezer).