How Long to Cook a Turkey in the Oven at 250 Degrees
It can take anywhere from 4 to 12 hours to bake a turkey at 250 degrees, depending on the size of your bird: Plan on 30 minutes per pound. Of course, the larger your turkey is, the less practical this cooking time becomes, so you'll likely want to set the temperature higher for all but the smallest birds. We recommend roasting a turkey at 325 degrees for the best results.
No matter what oven temperature you use or how large your turkey is, you'll know that it's done when the internal temperature of the meat reaches at least 165 degrees. Be sure to check it with a meat thermometer before you take the turkey out of the oven.