Add enough oil to the drippings left in the Dutch oven to equal about 1/2 cup. Heat over medium heat, then very slowly whisk in the flour. Cook the flour in the oil, whisking constantly to avoid lumps, for 20-25 minutes, until the roux is a very deep, golden brown. Fold in the onion, bell pepper, and celery. Cook, stirring frequently, for 8-10 minutes, until tender. While stirring, pour in 2 quarts of hot water. Bring to a boil. Return the chicken to the pot, then stir in the okra, garlic, bay leaves, Worcestershire sauce, Creole seasoning, thyme, and hot sauce. Reduce heat to low, and simmer, stirring occasionally, for 1 hour. Use a slotted spoon to remove the chicken, and place on a cutting board. Set aside. Return the sausage to the pot, and add the sliced green onions. Cook over low heat for an additional 30 minutes.