In a large skillet, brown the sliced andouille sausage and chicken halves over medium heat with a tablespoon of vegetable oil. Once they are browned evenly, remove from heat and set them aside.

In a dutch oven, mix the remaining oil and flour. Stir constantly for about 15-20 minutes until you achieve a dark, rich brown color to ensure depth in flavor.

Add the chopped onions, bell peppers, and celery to the pot. Season with salt and black pepper, stirring frequently until the vegetables are tender and aromatic, approximately 5 minutes.

Incorporate the garlic, thyme, oregano, paprika, and bay leaves into the mix. Cook these for another minute until their fragrance is released, enhancing the gumbo's aroma.

Stir in the browned sausage and chicken, making sure each piece is well coated with the vegetable and spice mixture. Let this cook for about 5-7 minutes to heat thoroughly.

Slowly pour in the chicken stock while continuously stirring. Add the can of diced tomatoes with green chilies. Bring the mixture to a gentle simmer. Lower the heat, cover, and let simmer for 1 hour, stirring occasionally.

Introduce the shrimp, crab meat, green onions, and parsley to the pot. Stir thoroughly, then cover and cook for about 5 more minutes until the shrimp turn pink and are cooked through. Adjust seasoning with more salt and pepper if needed.

Spoon the gumbo over a bed of cooked rice and sprinkle a slight dose of Filé powder for an authentic touch, if desired.