Prepare the Kalamazoo Smoker Cabinet smoker for 245°F smoking with a combination of hickory and cherry wood. We recommend allowing an hour for preheating.
Brush the chicken and the sausage on both sides with the oil and season with salt and pepper. Put the chicken and sausage on separate grates of the smoker, leaving a few inches between each thigh and link. Smoke the sausage until it reaches an internal temperature of 170℉ on an instant read thermometer about 45 minutes, remove to a plate and loosely tent with foil and let it rest for 15 minutes. Slice each link into ½ inch thick slices.
Smoke the chicken until it reaches an internal temperature of 170℉ on an instant read thermometer, about 90 minutes. Remove to a separate plate and loosely tend with foil while you prepare the gumbo. Cut each thigh into medium dice before adding to the gumbo
Heat the oil in a medium pot over medium heat until it begins to shimmer. Slowly whisk in the flour until a smooth paste forms. Switch to a wooden spoon and cook the roux over medium heat until it has darkened to a deep brown color, constantly stirring to ensure the flour does not burn. (There should be no black flecks in the roux. If there are burned bits, you will need to start over because the scorched taste of a burned roux cannot be fixed.)
When it’s ready, the roux will be a dark chocolate color. It will smell nutty and toasted. The cooking of the roux will take between 30-45 minutes total, depending on your stovetop. Let cool before using. The roux can be made 5 days in advance and stored tightly covered in the refrigerator.
Whisk together the chicken stock and cooled roux in a large Dutch oven until smooth, Stir in the peppers, celery, onion, garlic, cajun seasoning, black pepper, filé, and smoked andouille and let simmer for 45 minutes to 1 hour, until vegetables are soft and translucent and mixture has thickened slightly and the flour flavor has cooked out. Fold in the smoked chicken and cook for 5 minutes longer to heat through. Serve the gumbo in large bowls topped with a scoop of rice and garnish with chives.