Meanwhile, in a large, deep ovenproof skillet, toss the fennel, tomatoes, onions, both peppers and olive oil; season with salt. Set the chicken in the center of the vegetables. Pour in the stock. Roast for 1 hour and 10 minutes, until an instant-read thermometer inserted in the inner thigh registers 155°. Transfer to a carving board and let rest for 15 minutes.