[gundog]

Actually the reason the test birds laid thin shelled eggs was that they were fed a low calcium diet.

Cite that study please. Birds reserve calcium in their leg bones, and draw on the reserve for making shell. They do not use dietary calcium directly.

[Harmless Teddy Bear]

Go to junkscience.com and read their 100 things you should know about DDT.

And you have to have the stored calcium to draw on.

Having raised chickens I know that a low calcium diet does result in egg with thin shells and hens eating their own eggs to get back the minerals expended in the laying.