The best temperature for cooking a turkey in a convection oven depends on the size of your bird. If you're cooking a large turkey, such as a 20-pounder, set your oven to 325 degrees Fahrenheit and cook your bird for 1 hour. If you're cooking a smaller turkey or turkey breast, like a 10-pounder, set your oven to 350 degrees Fahrenheit (175 Celsius) and cook it for about 30 minutes per pound.
A good rule of thumb is to start checking the internal temperature of your bird after 30 minutes of roasting time. Check again every 10 minutes after that until it reaches 165 degrees Fahrenheit. This will ensure that your roasted turkey has reached an internal temperature high enough to cook it.