Who would have thought it?!

[Margo]

Making calcium powder from discarded egg shells.

metaspoon.com/eggshells-bak...

[Angel_of_the_North]

I also remember a recipe using a whole egg in lemon juice. Found it!

naturalnews.com/049087_calc...

It needs to be free range eggs, really, as the hens need access to decent grit to make good shells - I don't know if intensively raised hens get that.

[Silver_Fairy]

When I kept birds I would give them crushed egg shell mixed in with their grit, but on researching read that there isnt much calcium in egg shells.

[Margo in reply to Silver_Fairy]

That's interesting Silver_Fairy!