In general, poultry and game for roasting should be partly covered with thin slices of salt pork (barder), the exception to this being those game birds which are larded with thin strips of salt pork fat.
The purpose of this covering is not just to protect the breast from the heat of the oven but to avoid it from getting dry whilst the legs are being cooked, as these require more time for the heat to penetrate than do the breasts. The slices of fat should therefore cover the breast entirely and be kept in place by tying lightly with string.