Optical technique allows sexing of chicks before hatching, averting mass culling

A groundbreaking optical technique has been developed that allows researchers to identify the sex of chicks within chicken eggs before they hatch. This non-invasive innovation holds the potential to end the practice of sacrificing over 300 million male chicks annually, primarily in European hatcheries.

The method employs optical spectroscopy, a technique that uses light to reveal physical, chemical, or structural properties without direct contact. Traditionally used in fields like medicine and agriculture for tasks such as measuring fruit ripeness, this light-based approach is now being applied to the complex internal environment of an egg.

By illuminating the egg's internal structure, researchers can now determine the sex of the developing embryo. This advancement not only addresses the ethical dilemma of male chick culling but also offers the possibility of assessing egg quality and checking for fertilization. The study highlights that the way light propagates through an egg, a phenomenon previously overlooked, is key to this non-invasive analysis.

Male chicks are typically culled shortly after birth because they do not lay eggs and are not bred for meat due to slower growth rates. The new technique involves measuring how light particles, or photons, travel through intact eggs at various wavelengths. Researchers are studying how these photon effects change throughout embryonic development, offering a deeper understanding of the egg's interior without disturbing the developing chick.