How to Make It
Preheat the oven to 350°. In a large cast-iron casserole, heat the oil until shimmering. Season the chicken with salt and pepper. Add 3 of the legs to the casserole and cook over moderately high heat, turning once, until browned, about 10 minutes. Transfer to a plate and brown the remaining 3 legs over moderate heat.
Pour off the fat in the casserole. Add the bacon, onion, carrots and turnips and cook over moderately high heat, stirring, until barely softened, 2 to 3 minutes. Add the olives, thyme sprigs, bay leaf and stock. Nestle the chicken legs in the casserole so they are partially submerged and bring to a boil. Cover with a tight-fitting lid. Transfer the casserole to the oven and cook for about 45 minutes, until the chicken and vegetables are tender.
Transfer the chicken and vegetables to a platter; cover and keep warm. Strain the broth into a large measuring cup and skim off as much fat as possible. Return the broth to the casserole and boil until reduced by half, about 5 minutes. Season with salt and pepper. Return the chicken and vegetables to the casserole, cover and cook for 5 minutes to heat through, then serve.