Sprinkle chicken with salt and pepper. Dredge in flour, shaking off excess.
Cook chicken, in batches, in 2 Tbsp. hot oil in a large Dutch oven over medium-high heat 3 to 5 minutes on each side or until browned. Transfer to a plate, and wipe Dutch oven clean.
Add remaining 2 Tbsp. oil to Dutch oven, and heat over medium heat. Add mushrooms and next 4 ingredients, and cook, stirring occasionally, 5 minutes or until mushrooms are soft. Return chicken to Dutch oven, and add wine and next 3 ingredients.
Bring to a simmer. Cover, reduce heat to low, and cook 11/2 hours or until meat is tender enough to fall off the bone, basting chicken occasionally with liquid in Dutch oven. Remove and discard bay leaf. Season with salt and pepper to taste. Serve over Semolina Polenta; sprinkle with parsley just before serving.