I disagree; unless you're shooting a cartoon, everything should be as realistic and beleivable as possible. And everything in the movie should strive to be a work of art in itself.
Are we still talking about SciFi??
If the question implies "Chicken eggs", it all depends on what you mean by "chicken egg", is a chicken egg "an egg that was laid by a chicken" or "a egg that a chicken hatches from".
If it is the former, then the big answer is "The chicken", if it is the latter, the answer is "the egg".
The counterpart: What is meant by the 'Chicken"? Does it mean a thing that hatches out of a "Chicken egg" or the thing that lays a "Chicken egg".
"All my life I wanted to be someone; I guess I should have been more specific." -- Jane Wagner