Question: how long does a 1.8 kg chicken take to cook?
Answer: Roast for 20 minutes per 450g (1lb), plus 20 minutes in total. A 1.8kg (4lb) chicken will take 1 hour 40 minutes to cook. Baste the chicken 2-3 times with the cooking juices whilst it roasts and cover with foil as soon as it is golden brown.