Hi,
I tend to agree. A good broody will know what shes doing. It may put her off but even if it dosent she get quite agressive with you if she thinks you are threatening her babies. I know my girls would.
If she gets off the nest for some food and takes the first to hatch with her to the food bowl you mad be able to discreatly slip your hand in and disguard the shells but I find with broodies, the more you leave them to it, the happier they are.
Buffy