Preheat oven to 450 degrees. Spread wings in a roasting pan and roast, turning after 20 minutes. Cook until deeply browned, about 45 mins. Meanwhile, in a large stock pot heat oil over moderate heat until hot but not smoking. Add, onion, carrot, and celery. Cook until soft, stirring occasionaly, about 10 minutes. Add wings and any pan juices and reduce heat to low. Place roasting pan across two burners on high heat and cook until browned bits are sizzling. Add 2 cups cold water and bring to a boil, scraping up the browned bits. Pour liquid into pot and add enough cold water to cover ingredients by 1 inch. Raise heat to high and bring to a boil, skimming foam from the surface. Add the parsley, thyme, peppercorns and bay leaf. Reduce the geat to a simmer. Cook uncovered for 3 hours. Pour stock through a fine meshed sieve or a cheesecloth covered strainer. Let stand and skim fat from surface. Discard solids.