Defrost the chicken thoroughly for several hours at room temperature.
Heat the oven at 400F/200C/Gas Mark 6-7. Rub the chicken with the oil and dot with the butter. Sprinkle with herbs, if liked. Place in a well-greased roasting tin and cover with cooking foil.
Roast for 30-40 minutes, according to the size of the chicken pieces, until the juices run clear (not pink) when tested with a fork. (If still pink, cook for a few more minutes). Remove the foil for the last 10 minutes of cooking time to brown the chicken. Chipolata sausages, roast potatoes and parsnips can be cooked around the chicken pieces. Remove the chicken, and the sausages, potatoes, and parsnips (if used) from the tin, and keep warm. Use the juices left in the roasting tin to make the gravy.