Well since the modern chickens was first bred around 5,400 years ago I will assume that there needs have changed since then just like humans needs are different than the needs that our early ancestors.
Chris
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To be honest there are no such thing as a "Wild" Chicken. The closest living wild relative to chickens are Jungle Fowl.
The Jungle Fowl Hens lay far less eggs than a modern chicken so there needs for calcium is less.
Chris