But the answer is trivially obvious either way.
- "Chicken egg" meaning "egg laid by a chicken": laid by a chicken that came directly from a previous, ancestral species' egg...
- "Chicken egg" meaning "an egg containing a chicken": laid by that previous, ancestral species' egg. So one generation before the interpretation in 1).
Trivial. The only issue is your definition of "chicken egg", and the answer flips depending on that. Otherwise perfectly clear to me at least.