Even Americans who are careful to buy cage-free eggs typically aren’t aware that hundreds of millions of male chicks are killed each year. Every year the U.S. egg industry kills about 350 million male chicks because, while the fuzzy little animals are incredibly cute, they will never lay eggs, so have little monetary value.That longtime practice is changing, thanks to new technology that enables hatcheries to quickly peer into millions of fertilized eggs and spot male embryos, then grind them up for other uses before they mature into chicks.