1. Preheat oven to 425°.
2. Remove neck and giblets from pheasant; discard. Place pheasant in a small roasting pan coated with cooking spray. Starting at neck cavity, loosen skin from breast and drumsticks by inserting fingers, gently pushing between skin and meat. Rub 1/2 teaspoon salt and 1/2 teaspoon freshly ground pepper under loosened skin and over breast and drumsticks. Bake at 425° for 10 minutes. Cover legs with foil.
3. Reduce oven temperature to 350°. (Do not remove pheasant from oven.) Bake pheasant 30 minutes or until juices run clear. Cool. Remove and discard skin. Remove meat from bones; shred meat. Discard bones.
4. Melt butter in a small saucepan over medium-high heat. Gradually add flour to butter, stirring with a whisk until smooth. Cook 7 minutes or until dark brown, stirring constantly with a whisk. Remove from heat.
5. Heat oil in a Dutch oven over medium-high heat. Add yellow onion, bell pepper, and celery to pan; sauté 6 minutes, stirring occasionally. Add herbes de Provence, garlic, and bay leaves; saute 3 minutes, stirring constantly. Add shredded pheasant and sausage to pan; sauté 5 minutes. Add flour mixture; cook 30 seconds, stirring well. Stir in broth; bring to a boil. Reduce heat, and simmer 30 minutes (skim foam from surface, if necessary). Stir in Creole seasoning, Worcestershire, and hot pepper sauce; cook 30 minutes, stirring occasionally. Add oysters; cook 2 minutes or until edges begin to curl. Remove from heat. Stir in filé powder. Discard bay leaves. Serve over rice; sprinkle with green onions.