Place duck carcasses and next four ingredients in a large roasting pan. Spray contents with pan spray. Place in a preheated 400 degree oven for 1 1/2 hours, turning contents every 20 minutes until evenly browned. Add contents of the pan to a large stock pot. Pour some wine into the roasting pan to loosen any bits stuck to the pan. Pour liquid and loosened bits into the stock pot. Pour 2 cups of red wine into stock pot and enough water to just cover contents of the pot. Add peppercorns and bouquet garni. Simmer, uncovered over low heat for 6 – 8 hours, making sure that you keep enough liquid in the pot to just cover contents. Cool to room temperature and pour contents through a colander covered with cheesecloth. Discard stuff in colander. Transfer liquid (stock) to a medium stockpot. Simmer until liquid is reduced by one-half.