Remove chicken from marinade, let any excess drip off, and reserve marinade. Let chicken sit at room temperature while oven warms up, about 30 minutes.
04When the oven is heated, place potatoes, squash, and onions in bottom of a roasting pan, drizzle with any remaining marinade, remaining 1/4 cup oil, remaining 1 tablespoon salt, and season well freshly ground black pepper. Toss to coat. Place chicken, breast side up, on top of vegetables and roast until skin becomes brown and vegetables are starting to get tender, about 1 hour. Brush yogurt on chicken and continue roasting until chicken is well browned, juices run clear when inner thigh is pierced with a knife, legs move easily in the joint, and a meat thermometer inserted into the thickest portion of the thigh registers160 to 165 degrees F on an instant-read thermometer, about another 40 to 50 minutes. Let chicken rest at least 10 to 15 minutes before serving.