Heat oven to 350°F. Heat oil in large Dutch oven on medium. Pat chicken dry and season with 1/4 teaspoon each salt and pepper. Place skin side down in pan. Cook until golden brown, about 6 minutes. Turn and cook 3 minutes more. Transfer to plate.Add sausages to pot and cook until browned all over, 6 to 8 minutes. Transfer to cutting board; let cool before slicing.Add bacon to pot and cook, stirring occasionally, until golden brown and crisp, 8 to 10 minutes. With slotted spoon, transfer to paper towels. Discard all but 2 tablespoons of fat in pot. Add onion and 1/4 tsp salt to pot and cook, stirring occasionally, until golden brown and tender, 5 to 6 minutes. Add carrots and celery and cook 3 minutes more. Remove from heat. In small bowl, combine breadcrumbs, garlic, and thyme and set aside. Stir beans and broth into pot along with chicken, sausage, and bacon and sprinkle with crumb mixture.Bake until chicken is fork-tender and stew has thickened, about 11/2 hours. Heat broiler and broil until crumbs are golden brown, about 3 minutes Let stand 10 minutes before serving.