Modern chickens are bred to be either layers (for eggs) or broilers (for meat), with layers typically laying about 300 eggs per year, compared to their ancestors who only laid about two dozen eggs annually. Male birds of the layer breeds do not lay eggs, nor do they grow big enough to be used for meat. As a result, male chicks from flocks bred for the layer industry are humanely euthanized at the hatchery by trained personnel.
New research conducted at the University of McGill has created a non-invasive technology that can determine whether an egg is fertile, and whether the developing chick inside is a male or female. This determination can be done the day the egg is laid, using hyperspectral imaging. If the technology can be commercialized for the layer industry, it will eliminate the need to euthanize male chicks.
EFA published a blog post back in 2016, which discussed the issue of male chicks, titled The Complicated Practices of Egg Farmers: Chicken Selection, X-Ray Vision, and a Game of Whack-a-Mole.