Heat a medium, heavy duty skillet over medium-high heat. Add andouille sausage and cook, stirring occasionally, until browned, about 5 minutes. Transfer sausage to a large bowl. Add 1/2 cup water to skillet and scrape bottom to release any browned bits. Set this liquid aside.
Heat oil in an 8 quart Dutch oven over medium-high heat. Season chicken pieces with salt and pepper and saute until golden brown, about 4 minutes per side. Transfer chicken to bowl containing sausage.
Add the flour to the remaining oil in Dutch oven, stirring constantly with a wooden spoon over medium-high heat until roux turn caramel-colored, about 6-8 minutes. Add onion, stirring constantly until roux becomes the color of milk chocolate, 2-3 minutes. Add celery, bell pepper, and garlic, and cook, stirring often, until vegetables are softened, about 4 minutes. Stir in chicken broth, 1 qt of water, the reserve sausage liquid, and the andouille, chicken, bay leaves, and thyme.
Bring to boil, reduce heat, and simmer uncovered until chicken is falling off the bone, about 45 minutes.
Transfer chicken pieces to a plate and allow to cool. Once cooled, remove skin and bones from chicken, pull meat into bite size pieces and return to gumbo. Season to taste with salt and pepper if needed.
Serve in large bowls over 1/4 cup of hot cooked rice per serving. Add scallions and hot sauce to taste. Pass file at the table for everyone to add to taste.