Give her some credit, yes she can tell which ones are good and which ones are bad. I don't know how, but she can tell. My broodies always roll out the bad ones and stay on the good ones. It's their way of not letting the good ones go bad or get bacteria or something. I also had another one eat 2 of her bad ones. It's normal. If she does that to all of them though, you've got a problem.
