Put 1/2 cup olive oil in a skillet and get it very hot. Add the flour slowly while stirring constantly until the roux turns a medium dark brown (10-15 minutes). The roux will burn easily so watch it and stir constantly! Add the sautéed vegetables and the sausage to the roux and sauté 3 more minutes. Transfer the vegetables and sausage to the 10 quart pot and add the stewed tomatoes, tomatoes and chilies, beer, 5 cups of duck broth, Worcestershire sauce, black pepper, salt, bay leaves, and thyme and cook 30 minutes. Separate the duck meat from the bones, and add the meat and the okra to the gumbo and cook 1 hour. If the gumbo loses too much moisture, add more beer. Serve over white rice.