Researchers have described a straightforward way to determine the sex of developing eggs during the early stages of incubation. The work was reported by the University of California Davis. The goal is to identify the sex before the embryos are fully formed, so hatcheries can avoid separating and culling male chicks after hatching. This shift could unlock billions of eggs for alternative humane uses, reducing both waste and the environmental footprint of poultry production.
In many laying hens facilities, staff currently separate male and female chicks the day after hatching, with the males culled soon after. The proposed method could end this practice by enabling an early, reliable determination of sex inside the egg. Several European countries have already enacted policies to phase out the routine culling of male chicks, underscoring a broader movement toward more humane poultry farming. The traditional sexing methods often rely on looking inside the egg or puncturing it, techniques that are most useful in later stages of embryo development. The new approach seeks to identify the sex during the egg stage itself, potentially changing the economics of hatcheries and welfare outcomes alike.
The core idea behind the new technique is to detect organic signatures that emanate from the developing embryo within the shell. Instead of breaking the egg, the researchers adapted suction cup technology used in industrial egg processing to draw a sample of the air near the shell. This sampling does not require opening the egg. The collected air is then analyzed in a laboratory using advanced instrumental methods, including gas chromatography and mass spectrometry. By correlating specific chemical markers with the presence of rooster versus hen embryos, the team established a statistical relationship that can indicate the sex of the embryo without direct intervention.
In practice, the method allows rapid screening of large egg lots. Vacuum-based sampling can be deployed to test many eggs at once, enabling hatcheries to sort eggs by sex before incubation or at very early stages of incubation. The researchers emphasize that the speed and scale of this approach could fit well with commercial operations, reducing downtime and improving workflow efficiency while aligning with welfare goals.
The authors of the study hope the technique will help farmers reduce operating costs and promote more humane production practices. If adopted widely, this method could shift the economics of hatcheries, enabling resources to be redirected toward products or uses that add value without sacrificing animal welfare. It remains an area of active research and collaboration with industry partners, with ongoing work aimed at refining accuracy, speed, and cost-effectiveness to suit different farm sizes and species variations. The broader implication is a poultry industry that produces eggs and chicks with fewer ethical tradeoffs and with less environmental impact, as fewer male chicks are discarded after birth. Attribution: UC Davis researchers and affiliated institutions.