It can take approximately two to four hours to cook a turkey in a bag, depending on the size. A turkey weighing 12 to 15 pounds takes two hours to cook, while a 20- to 40-pound turkey cooks in about four hours.
Reynolds produces oven bags specifically designed for cooking turkeys. A cook can use a bag by putting the oven bag in a roasting pan, spraying the inside of the bag with cooking spray and coating it with flour. Nylon ties are included in the package to seal the bag. Roasting the turkey in an oven at 350 degrees Fahrenheit typically yields the best results.