Well, this is why it's an experiment! I'm pretty sure it will be de-bunked, but sometimes old wives' tales develop for a reason.
(To speckledhen: Yes, the hatchery argument was one of my very first evidences to debunk this hypothesis. But then I discovered a patent application online for an optical device that compares egg shape and sorts eggs accordingly. It is explained that the reason it is not in use yet is because the parameters are different for each hen. Some lay generally rounded eggs, and some generally pointy eggs, but within their clutch there is variety. So the parameters would have to be set to evaluate each hen's eggs differently.) This being considered, you are right that there is a flaw. The improved experiment would have people doing only eggs from one hen and sorting them in comparison to eachother. (btw, Thanks for joining the game!)
Anyway, I understand everyone's skepticism. However, as a biology teacher, I enjoy experiments and thought this would be a good way to come up with an answer once and for all, and participation wouldn't be too hard, for people who thought it would be fun to try.
I wouldn't have even done it except for one thing - Yes, the hen does donate the chromosome that determines gender. But they also form the egg! And the calcium shell isn't formed until
after the zygote forms.
... so... maybe!! Thanks to all of you who are participating!