This thread is a year old, some of the folks posting may not follow it closely (or at all) any more.
As to "white shop n save" eggs, I don't know that brand. The experimental grocery store eggs I hatched were from Trader Joe's Markets in the Central California Valley area; not all TJs sell fertile eggs.
This thread was originally started as a comparison between Whole Foods and Trader Joe's for folks deliberately wanting to just see if they personally can hatch refrigerated grocery store eggs.
It just so happened white Leghorns are a fantastic laying breed (duh - in the business to sell eggs, that's what you wanna raise) so spending less than three bucks for a dozen fertile eggs to HATCH out great layers ranks up there as a good - and fun! - plan to increase one's flock.
My Josie, hatched 1/1/11, is friendly, curious, attractive, egg laying queen!