I wouldn't cook it at 250. By the time you get the inside hot enough to kill bacteria(160F) the outside will be as dry as cardboard.
Try this recipe from Alton Brown
1 half hour at 500F
Cover breast with foil
Cook 1.5-2 hours at 350F until meat thermometer reaches 160F
Also, you might want to get an oven thermometer to make sure your oven is getting to temperature you are setting it at. Many ovens are amazingly inaccurate. Mine is off by 50 degrees.
http://www.foodnetwork.com/cooking-perfect-turkey/video/index.html
At 350 degrees you usually cook the turkey for 20 minutes per pound, but at the low temperature of 250 you'll need to cook it for 6 to 8 hours. Check with a meat thermometer and make sure if reaches 165 or higher in the deepest part of the turkey.
That would depend on how accurate your oven temperature is as well as the starting temperature of the turkey. Turkey is considered safe to eat when it has an internal temperature of 165 degrees.
I smoked turkey for 2 hrs can i cook it in roaster at 250
8 1/2 hours
It's usually 20 minutes per pound at 250 degrees
11 hours
3 1/2 hours
6 hrs
A turkey crown takes around 20 minutes per pound to cook. A 10 pound turkey crown will take at least 3 hours and 20 minutes.
how long does it take to cook 2-20 pd turkey
325 degrees
A 4.3 pound turkey should be cooked in a fryer for at least 13 minutes. The turkey should have an internal temperature of 160 degrees.
A 5 kg turkey should cook for about 3 hours if unstuffed in the over. If the turkey is stuffed, it should cook for about 3.5 hours.
A 5.6 kg turkey will take about 3 to 3 and a half hours long to cook. The oven temperature should be set to 190 degrees Celsius/375 degrees Fahrenheit.
pound*
It will take a couple of hours to thaw out a turkey leg before its ready to cook. It should take about 2 hours.
450 degrees is too hot to cook a turkey because it will become dry. If you are cooking it in the oven, follow the directions on the plastic packaging that comes around your turkey. Usually about 350 degrees is better because you want to cook a turkey slow until the fork goes in easily about 5 to 8 hours of cooking time, unless you are deep frying it then that is a different procedure.
How long do you bake a 5-6 pound turkey roll and at what temperature?
20 minutes