I was composting eggshells from breakfast when my chicken ran over and grabbed a beak full and poceeded to gobble it down in a matter of seconds. Is this good for her? Will it make her start eating her own eggs?
It is good for her, and I don't think chickens have the mental capacity to connect broken eggshells with what's inside whole eggs. I feed eggshells to mine and haven't had any problems, although I take the perhaps unnecessary precaution of crushing them. (I just step on them after I toss them on the ground.)
It shouldn't cause any trouble with her eating eggs. A LOT of people feed their shells back to their chickens (I am one of those) and it is a great way for them to get extra calcium. Just crush them really tiny and give them back and you won't have to worry about her stealing them.