For a fully cooked turkey, it takes about seven minutes per pound. Although the turkey is already cooked, it may have formed bacteria, and it should be put it in the oven for that time to get to a safe internal temperature.
Pre-cooked turkeys are very convenient, as they do not take as long to cook as a fresh bird does. They are also ideal for people who have not have a lot of confidence on their cooking skills. Although cooking a fresh turkey is not really complicated, it may take some tries for some people to perfect their techniques with seasoning.