I love all things Nigella Lawson. One of her books, "How To Eat", is just a super charming book and the reason why i now love reading cookbooks. This book is like a biographical novel; she tells wonderful stories about her experiences and family. One in particular is about how her mom used to roast a couple of fryers a week.
I loved this idea and immediately tried it (now every week, but every other).
And since i am the type that usually would call my mom every time i needed help figuring out how long to cook my birds, i was very excited to see such a hard and fast rule.
Dressing your chicken how you like (evoo and herbs or citrus or garlic, what have you...), place it, covered with alum. foil tent, in a 400 degree oven for 15 minutes per # + 10 minutes extra. After retrieving it from the oven, you let it to rest for 10 minutes before you carve it.
And the *WHOLE* trick to a moist and tender breast of chicken every time is:
roast it upside down--breasts on the bottom.