OK, thanks. Since the majority of the shells are from Walmart eggs and they're all white so I can't tell the organic ones apart from the Walmart ones, I'll just toss them and stick to safer sources of calcium. Besides, I've been worrying about what someone might say if they came in and saw a jar of eggshells saved on the counter. Non-chicken people probably wouldn't understand.
In the old day's people saved the eggshell's for also adding to the mulch piles that would go into the garden's. I don't see where it would be a big deal to save them for the chicken's. Non-chicken people could get a lesson from you.