Question: how long does it take to cook a 1.5 kg chicken?
Answer: A 1.5kg chicken will be perfectly roasted after 1 hr 20 mins at 190C/fan... 170C/gas 5. It doesn't matter what you stuff into it, rub or sprinkle over it or put around it, this timing never changes. Remember this and you will always be able to roast a chicken.