Chicken and Sausage Gumbo

1 whole chicken, cut up and cubed
1 pound smoked sausage
1 cup chopped onion
1 cup chopped celery
1 cup chopped green bell pepper
3 quarts chicken stock
4 cups steamed rice
1/2 cup flour
1/2 cup oil

Make a dark brown roux by heating the oil over medium heat in a large stock pot. Add the flour and stir. Continue stirring until the roux is smooth and dark brown. Sauté the onion, celery and bell pepper in the roux until tender. Add the chicken and brown. Slowly add in the chicken stock. Fry the sausage in a separate pan and drain, then add to the gumbo. Simmer for 1-1½ hours. Season with salt and pepper to taste.