Wash duck parts well and place them in a large stockpot. Add cold water to cover by about 5 cm and slowly bring to a boil, skimming all of the froth from the surface as it forms. Lower the heat and add all of the remaining ingredients except the peppercorns. Simmer, uncovered, for 3 hours. Add water as needed to cover the ingredients and skim when necessary. Add peppercorns for the last fifteen minutes of the simmering process. Strain the "soup" into a large bowl through a colander lined with a double layer of dampened cheesecloth. Gently press the solids to extract all of the liquid possible. Discard the solids and cool the liquid to room temperature. Refrigerate until chilled and lift off the solid fat that forms at the surface. Discard the fats. Pour the stock into containers for storage, label and date. Stock keeps for about 3 days in the refrigerator, and up to six months in the freezer.