Season the turkey legs with kosher salt and black pepper and place in a Crockpot with 4 cups of the turkey broth (or chicken broth). Cover and cook on on High for 5 to 6 hours or on Low for 8 to 10 hours.
Shred the cooked turkey leg quarters with tongs or a fork. Discard the bones.
Preheat the oven to 425 degrees F.
On a rimmed baking sheet, spread out the flour and place in the oven and bake for about 40 minutes until it turns the color of cinnamon. Keep a close eye on it after the first 30 minutes to make sure the roux doesn't burn!
Meanwhile, place a Dutch oven on the stovetop over medium heat. Add vegetable oil, onion, bell pepper, and celery and sauté for about 5 minutes, stirring often.
Add minced garlic, bay leaves, thyme, Worcestershire sauce, and Tony's Creole seasoning. Stir constantly for 1 minute.
Transfer 4 cups of the turkey broth or chicken broth from the Crockpot to the Dutch oven and stir well to combine. Bring to boil, then reduce heat to medium low and simmer until the dry roux is the color of cinnamon.
Remove the dry roux from the oven and transfer to a mixing bowl. Gradually add the remaining 2 cups of turkey broth or chicken broth (room temperature) to the roux, whisking constantly, so it absorbs evenly.
Add the roux mixture to the Dutch oven, whisking constantly to thicken the gumbo.
Add sliced andouille sausage and let the gumbo simmer another 5 minutes, stirring occasionally.
Remove the bay leaves from the gumbo and discard.
Remove Dutch oven from the heat. Add chopped green onions and shredded turkey meat to the Dutch oven and stir to combine. Sprinkle with filé powder, if desired.
To serve, place about ⅓ cup of rice in each bowl and top with about 1 ½ cups sausage and turkey gumbo over the top, making sure each person gets some turkey and sausage.