Place a Dutch oven or stock pot over medium heat and coat with cooking oil. Add carcass, gizzards, onion, carrots, thyme, garlic, ginger, bouillon cube, parsley, peppercorns and bay leaves. Pour in only enough cold water to cover (3 quarts). Too much water will make the broth taste weak. Allow to slowly come to a boil. Lower the heat to medium-low and gently simmer for 2 to 3 hours. As it cooks, skim any impurities that rise to the surface. Add a little more water if necessary to keep carcass, bones and veggies covered while simmering.