Add oil to a 6 quart Dutch oven or similar heavy bottomed pot over medium heat. Sprinkle in flour while whisking constantly. Cook stirring slowly and constantly for 30-45 minutes OR until the color is dark brown and similar to the color of chocolate. (Time can vary depending on the consistency of the heat setting. Go by color.)
Once desired color is reached, to the roux add diced onions, celery, bell peppers and garlic. Stir to coat in roux, cooking for 4 to 5 minutes, or just until vegetables have softened.
To the pot add Cajun seasoning, salt, cayenne, and bay leaves. Continue to stir cooking for 3 to 4 minutes. Add 6 cups chicken stock. Stir until the roux mixture and stock are well combined. Bring to a boil, then immediately reduce heat to medium-low. Cook, covered for 1 hour.
Meanwhile, in a medium size skillet, brown okra in 1 Tbsp butter. Cook over medium high just until okra dries out a bit. Set aside.
After 1 hour to the pot add okra, andouille sausage and chicken. Continue to simmer over medium-low gently bubbling with lid slightly offset for an additional 45-60 minutes.
Remove from the heat and discard bay leaves. Stir in 1/2 green onions, parsley and file powder. Mix well. (If you'd like a thinner broth add additional chicken stock to thin.)
Serve in shallow bowls with cooked white rice garnished with reserved green onions and hot sauce.