These birds are most likely all Leghorn hybrids, and all the Leghorns I've ever owned were very scrappy survivors.
I think when you consider that a chick is born under their mom's butt, have to chase her around their habitat at only a couple days of age, and endure attacks from jealous hens, roosters, etc., as well as predator attacks, that they are probably a lot tougher than we give them credit for.
I am a proud meat eater and have no problem with keeping animals as livestock and not as pets. I recognize that the vast majority of chickens are kept strictly for their intrinsic monetary value as a farm animal.
However, I'm not a fan of factory farming either. It's a fact of life though, no matter how untasteful it is. If there is any silver lining to it, they are probably the reason we can buy production quality hens for such good prices. And as others have said, the more chickens private individuals keep for eggs, the less demand there will be for these factory chicken eggs.
Anyone else notice they never showed the "wood chipper" they are reputed to use to cull males?
Oh, and those birds are specially bred to be feather sexed. Not all breeds can be sexed that way...