In a heavy 2-quart saucepan stir together flour and oil until smooth. Cook over medium-high heat for 4 minutes, stirring constantly. Reduce heat to medium. Continue to cook, stirring constantly, for about 15 minutes more or until roux is dark reddish brown. Let roux cool.
Add chicken broth to a 3 1/2 to 6-quart slow cooker and Stir in roux.
Add sausage, chicken, okra, onion, green pepper, celery, garlic, salt, pepper, and red pepper.
Cover and cook on LOW for 8 to 10 hours, or HIGH for 4 to 5 hours.
Serve with hot cooked rice.
Use a gluten free flour for the roux. I used rice flour.