- To a stock pot over medium-high heat, add turkey bones and 5 quarts cold water. Cover and bring to a boil, then remove lid and reduce heat to medium. Let simmer for 1 hour.
- Bring a pot of water to a boil; prepare an ice bath. Add okra to boiling water and blanch for 2 minutes. Use a slotted spoon to remove okra from boiling water and transfer to ice bath. Drain okra and set aside.
- After stock has simmered 30 minutes, begin the roux: In an 8- to 10-inch cast-iron skillet, heat vegetable oil over medium heat. When oil is hot, whisk in flour until fully incorporated. Continue cooking, stirring constantly with a wooden spoon, until roux takes on color of peanut butter, about 30 minutes.
- Transfer roux to a 4- to 6-quart stockpot or dutch oven. Add onions and cook, stirring, for 45 seconds. Add bell peppers and celery and cook, stirring, for another 45 seconds. Add garlic.
- Strain stock. Add 2½ quarts of stock in three increments to the roux, stirring after each addition. Add next six ingredients and simmer for at least 2 hours.
- Meanwhile in a sauté pan, brown andouille sausage for 6 to 8 minutes on medium-high heat. Add it to the simmering gumbo, followed by the reserved turkey meat. Season with more salt to taste. If gumbo is too thick, add more stock to reach your desired consistency.