In the chicken and egg industry, rooster chicks are worthless. They cannot become laying hens and they also do not become food, as they do not gain weight fast enough.
Instead, they are "discarded", as they say in the industry language. This means that the chickens are killed immediately after hatching with gas or grinding.
"In Sweden, there are about four to five million rooster chickens that are killed each year," says Marie Lönneskog Hogstadius, operations manager at the trade organization Svenska Egg, which is based at the Vreta Kluster business park north of Linköping.
There is ongoing research around the world to find methods for sorting eggs. But nobody has yet a working commercial solution that can be used on any large scale.
The furthest have come in Canada, Germany and the Netherlands. Optical technology or DNA analysis is used there.
Together with researchers at Linköping University, Svenska Ägg is running a project where a method has been developed where the eggs are sorted by sex on the same day as the hen puts it.
- It is a completely in-house method that we are now testing and verifying in a production environment. In a month we know if it works. If it does, then we can scale up the tests, says Anita Lloyd Spetz, professor emeritus at Linköping University.
The method is to analyze the differences in the gases that the eggs emit and which can reveal the sex of the embryo. The researchers do not want to be more precise than the process they have developed, because they are about future patents that can be worth big money in a commercial market.
- If you find a method that is efficient and commercially viable, there is a lot to gain. Handling becomes easier, as only half as many eggs need to be hatched, says Marie Lönneskog Hogstadius.