Slow-cook duck overnight in water only. Debone. Mince. Cover tightly to prevent drying. Set aside.
Add 9 cups well-strained duck broth to 2-gallon pot. Add water to bring to 9 cups if necessary.
Mix seasonings well. Add all vegetables but okra and seasonings to broth. Stir well.
Simmer until onions are translucent. Remove from heat.
In heavy skillet, heat oil and slowly whisk in flour. Stir constantly over low-medium heat until roux is chocolate brown.
Remove roux from heat and let rest 10-15 minutes.
Add roux to pot. Mix well.
Add duck, okra, and andouille. Mix well.
Simmer until okra just becomes tender.
Add shrimp and crawfish. Simmer 5-10 minutes.
Serve with rice. Freezes well.