Make a roux by heating oil in a large cast-iron or heavy-bottomed pot over high heat; whisk flour into hot oil. It will immediately sizzle. Reduce heat to medium; continue whisking until roux is the color of peanut butter, about 15 minutes. Add onions, stirring into roux with a wooden spoon. Reduce heat to medium-low; continue stirring until roux is brown, about 10 minutes.

Season duck with Creole spice. Add duck to pot, increase heat to medium, and cook, turning pieces until browned, about 10 minutes.

Add chicken sausage and stir for 1 minute; add bell pep- pers, celery, and garlic. Cook, stirring, about 3 minutes. Add green onions, chicken stock, and bay leaves. Bring gumbo to a boil, stirring occasionally. Reduce heat to medium-low and simmer for 45 minutes; stir occasionally, skimming off fat from surface of gumbo as it simmers.

Add andouille, and Worcestershire. Season with salt, pepper, and Tabasco. Simmer for another 45 minutes, continuing to skim fat from surface.

Add oysters and oyster liquor just before serving. Serve in bowls over rice.