Harnessing the Potential of Precise Gene Editing to Eliminate Male Chick Culling

Every year, over 1.5 trillion eggs are consumed globally, sourced from over 7 billion laying hens. A significant ethical dilemma arises from the widespread practice of indiscriminately incubating and subsequently culling male chicks, a by-product unwanted by both the egg and meat industries due to their inability to lay eggs and insufficient muscle growth. This practice also imposes a substantial financial burden on the egg industry. Here, we present a novel solution for sex detection in freshly laid eggs using the CRISPR/Cas9 gene-editing tool. Our approach integrates two complementary components: first, by introducing a fluorescent biomarker on the male chromosome, we create a chicken line endowed with a sex-detectability trait. As a result, male offspring fluoresce, while females, together with their eggs, remain non-fluorescent and genetically unaltered. Second, we develop an electro-optical scanner designed to detect and automatically remove all fluorescently labelled eggs containing male embryos before incubation, creating a female-only environment within the hatchery. By eliminating male chick culling, our solution enables hatcheries to selectively incubate female eggs. By sparing the unnecessary incubation of male eggs, this could significantly enhance hatchery efficiency and egg production, potentially doubling global egg supplies. This study underscores the transformative potential of advanced gene-editing tools in resolving critical challenges within the livestock industry.