I found that my five pound chicken took about two hours. The general rule for estimating the cooking time for a perfect roast chicken recipe is to give it about half an hour per pound at 400 degrees F, but ovens do vary as do roasted chicken holiday dinner recipes. For this reason, double-check with your instant-read thermometer. When the internal temperature in the thickest part of the thigh registers over 165 degrees F, you can begin to dry the bird out. So whether you prefer dark meat, breast meat or some of each, you’ll want it juicy and perfectly cooked for the best result.