There is some debate on the oven-roasting temperature for a roast chicken, and typically, it is fairly foolproof. With 2 different temperatures here, it's a smart way to ensure crisp skin and meat that is fully cooked through without being dried out. For this recipe set the oven initially to 220c. After 20-30 minutes and once the skin is browned, lower it to 140c for a further 30-40 minutes.