Even though your turkey will be in the oven for hours, it is still important to make sure it is fully COOKED all the way through before you chow down. Your turkey may look golden brown and delicious, but a food thermometer is the only way to know that your turkey has reached the safe minimum internal temperature of 165 degrees.
USDA - Four Steps for a Food Safe Thanksgiving Feast https://www.usda.gov/.../four-steps-food-safe...
Original source can be found here.