I'm guessing you cook a huge joint then cos I've just cooked a 2kg chicken in just over an hour?
Meat is generally quick to cook if it's a small joint suitable for 2 people.
I tend to buy joints around 1kg in weight, i often buy basted chicken brest too.
This is so that i can get a couple of meals, & a couple of butties out of of the meat, being single & living alone means, so when i do a roast, i then with the leftover meat, i either do a curry, or stir fry, for the next day.