I have some White Leghorns I hatched from refrigerated, grocery store eggs (Trader Joe's) on New Year's Day. Three pullets and a cockerel. They are part of my large, multi-breed flock, and aren't old enough to start laying yet.
They are quite flighty, and shy. But they forage very well - my flock ranges freely on an acre - and eat less feed than many other breeds. From my study, I know they're going to be great layers. They're awfully pretty.