If you parboil chicken before you grill or cook them, it’ll render down the fat on the chicken which will end up turning very crispy when they’ve been fully cooked. Parboiling will make sure the moisture and the juices stay inside the chicken and that when you go on to cook them further they do not dry out. Parboiling is best when you plan to cook or grill chicken wings as the skin and fat on the outside of the wings will go crispy.