In a kettle combine the fowl, the neck and the giblets, and dozen cups cold water, bring the water to a boil, and skim the froth. Add half cup cold water, bring the stock to s simmer, and skim any froth. Add the onion, the leeks, the carrots, the celer, the salt, and the parsley, thyme, garlic clove, and bay leaf and simmer the stock, skimming the froth for 2 hours. Remove the fowl from the kettle, remove the meat and skin from the carcass, and reserve the meat for another use. Chop the carcass, return it and the skin to the kettle, and simmer stock, adding boiling water if necessary to keep ingredients barely covered, for 2 more hours. Strain the stock through a fine sieve into a bowl, pressing hard on the solids, and let it cool. Chill the stock and remove the fat. The stock may be frozen. Make 6 cups.