For the dry roux: In a heavy skillet over medium-high heat, heat the flour, stirring constantly with a spatula or whisk that scrapes the bottom of the skillet clean. Stir constantly to keep the flour browning evenly. When steam comes off the flour, reduce heat and keep stirring. Do not burn. Continue until it reaches a tan color. To test, remove from heat, stirring for 1 minute off-heat and place some of the mixture into a drop or two of water and force it to mix with the back of a spoon. You are looking for a mahogany color. When complete,remove from heat and continue stirring until cooking stops; then let stand a while to cool. This can be made ahead and stored in a zip-lock freezer bag in the freezer.
Remove the skin and fat from the chicken. Cook with water to cover and cool. Debone and chop the chicken into small chunks. Reserve the liquid.
In another large skillet, over a medium flame with a small amount of oil, heat the onions, peppers and celery; cook until the onions are clear, then add the smoked sausage and andouille. Add the broth from above and the garlic. Bring to a boil and reduce to a simmer. Mix the roux with water, whisking to be sure the roux is evenly wet and add to the gumbo. Now check the liquid, adding some broth or hot water if needed. It should have the color of the roux and be just slightly thickened. Simmer for about 30 minutes. Add salt and black pepper to taste, then add ground red (cayenne) pepper -- enough to just prick the tongue. About 5- 10 minutes before removing from heat, add the green onion tops and parsley. To serve, put a scoop of rice in your bowl and ladle on the gumbo. You should have plenty of French bread to complete your meal, and then top it off with a good tossed salad.