In-ovo sexing

In poultry farming, in-ovo sexing is method for determining the sex of a chick while it is still in ovo (Latin for "inside the egg"). There are various methods to determine a chick's sex in the 21-day incubation period before it hatches. In-ovo sexing technology has branched into two categories, DNA based and Image based. The first technology to be successfully commercially introduced for poultry farming was bio-marker detection through the Dutch–German company Seleggt in November 2018. Meanwhile, image based in-ovo sexing technologies have been introduced to the market by the German start-up Orbem and AAT, a subsidiary of the EW Group.

History

Background

In-ovo sexing is a method of culling male chicks, before they hatch, though the industry often prefers terms that make this less apparent, such as "pre-hatching selection" or "sex identification". Historically, the term refers to culling male chicks, by direct physical inspection, after they hatch. Generally, in this article, "culling" is used in its historical sense, to refer to male culling after hatching. Now that it has become possible to cull male chicks prior to hatching, the tradition practice of culling male chicks after they hatch raises new ethical problems. Modern poultry farming divides chickens into two genetic breeds: layers, which are raised for eggs, and broilers, which are raised for meat. Male layers have low economic value, as they cannot lay eggs and are less suited for meat production than broilers. As a result, many chick hatcheries opt to cull their male layer chicks as a cheaper alternative to raising them. Under conventional practices the male and female chicks are manually separated by human sexers on the same day they hatch. The female chicks are then transported to rearing and laying farms to be raised as egg-laying hens, while the male chicks are culled. It is estimated that 7 billion one-day-old male chicks are killed each year through chick culling.

Benefits of in-ovo sexing By enabling producers to identify and remove male eggs before they hatch, in-ovo sexing offers a solution to chick culling. Unhatched male eggs can be used for different purposes, such as alternative high-value protein sources. In addition to its welfare benefits, in-ovo sexing offers some economic benefits. It allows producers to avoid wasting energy and incubator space on unwanted eggs. And by limiting the egg pool to only females, it makes other technological interventions like on-farm hatching and in-ovo vaccination more cost-effective.

Male-chick culling ban Several European countries have passed laws to restrict chick culling. In January 2021, Germany was the first country to successfully outlaw the practice. A few months later, France also banned the one-day-old male chick slaughter. In 2022, the third country, Italy, followed the same steps, prohibiting the practice by 2026. Efforts have been made to push an EU-wide ban with standardized regulation for all countries. In 2024, the UK government's official Animal Welfare Committee recommended that the UK ban chick culling, although their recommendation is not legally binding. In the US, male culling has received substantial attention from animal activists, although no legislation has been passed. The egg industry has indicated that they will strongly support the adoption of in-ovo sexing technology once it is available. A number of state governments in India have mandated that in-ovo sexing be used once it becomes available.

Academic research For a long time it was unknown how to determine the sex of an egg before hatching. The poultry sector has worked to develop an approach to sexing before hatch in order to phase out chick culling in the interest of animal welfare. The first study on in-ovo sexing was published in 2013. The researched procedure, later called bio-marker detection, used a hormonal test for the allantoic fluid of brown layers’ eggs and was able to sex eggs by day 9 of incubation. Further research was done by Prof. Dr. Einspanier following the same methodology. This method was found to affect egg hatchability. In 2016, the fluorescence spectroscopy methodology was developed, analyzing the extraembryonic blood to determine the sex of the embryo through its blood wavelength. The supervised egg classification by a PC with a 93% error rate was able to determine the sex of 380 eggs at 3.5 incubation day. In 2017 a variation of this methodology was developed, pattern analysis in hyperspectral images. Under this method, the eggs are first candled with halogen lamps. Next, a hyperspectral camera collects the transmitted light and the eggs are classified using a linear discriminant analysis. This methodology can perform in-ovo sexing from day 11 to day 14 with a 97% accuracy. In 2019, a new methodology of AI-powered imaging was developed, combining AI and MRI to perform in-ovo sexing on day 12 with 95% accuracy. MRI had previously been used since 2007 for studying egg development in a contactless manner, but it wasn't suitable for large-scale in-ovo sexing until it was combined with AI.

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