Originally Posted by Kayelle
Sure, you can cut into it if you don't care about keeping the juices inside. Maybe you need a new thermometer? I can't even imagine how dry and overcooked two completely defrosted chicken breasts would be after 1 hr. at 400 degrees!
My dad would have said, "It's already dead. You don't need to kill it again."
Personally, I would not roast chicken breasts that weren't on the whole bird. They cook so quickly that overcooking is always a danger.