Looking at the word "addle" again, and the statement that rough handling of an egg can prevent an embryo from forming, I was remided of seeing a mother duck each day carefully turning over the eggs she was hatching . Marvelous that it could be pregrammed into her to protect the embryos from undesirable effects of always being in one position.
Edit: Hey, WW: a prof right near you has a URL about the white vs red acorns. Very interesting!
http://www.bbc.co.uk/nature/animals/mammals/tv/science_4.shtml