Usually cook poultry 15 minutes per lb. but 10 lb is a big bird and 150 minutes might be too long. cook it for 45 minutes and check the looseness of its joints, the color of the juice. when the juice runs clear it is ready if it is still pink it needs more time or check with a thermometer.ook for 20 min at 400 F, reduce the heat to 350 F and then cook 15-20 min per pound. So all told your birdie should be in the oven for about 2.5 to 3 hrs.