Cooking a 14-pound turkey can be a delightful experience! Generally, you should roast it at 325°F. It typically takes about 3 to 3.75 hours if it's unstuffed, and slightly longer if stuffed. Make sure to use a meat thermometer to check that the internal temperature reaches 165°F in the thickest part. Are you preparing the turkey for a special occasion? I'd love to hear more about it!