The culling of male day-old chicks from laying lines has been a subject of controversy within the agricultural sector and among consumers for years. As these lines are bred for egg-laying performance, the male chicks gain very little weight and are therefore regarded as ‘unwanted by-products’. As a result, around 45 million¹ chicks were killed shortly after hatching each year in Germany up until 2022. However, since 1 January 2022, the killing of male day-old chicks has been banned in Germany. Alternatives include sexing in the egg, fattening male chickens – so-called ‘broiler chicks’ – and breeding dual-purpose breeds². Although dual-purpose breeds do not achieve the same performance levels as animals from traditional laying and broiler lines, the hens are suitable for egg production and the chicks for meat production.

The draft bill to end chick c¹ulling initially provided that, from 1 January 2024, only methods of sex determination in the egg commencing before the 7th day of incubation would be permitted. The reason for this was that there were uncertainties regarding when pain sensitivity begins in chicks. However, a study funded by the Federal Ministry of Food and Agriculture (BMEL) concluded in 2023 that it can be assumed that no sensation of pain is³ present up to and including the 12th day of incubation. Consequently, on 16 June 2023, the Bundestag passed an amendment to the Animal Welfare Act banning the culling of chicks, under which sex determination in the egg may now be carried out up to and including the 12th day of incubation, followed by the culling of male embryos.
The amendment has met with broad approval from the industry, as the new law allows current sex determination methods to continue to be used. Accordingly, the “Association for Controlled Alternative Husbandry Methods” (KAT) announced that, from 1 January 2024, KAT-certified eggs may only be marketed if they were laid by a hen originating from a hatchery where alternative methods to chick culling were used. These eggs are also labelled⁴ as “without chick culling” (OKT).

The following provides an overview of the methods currently permitted for sex determination in the egg. Regardless of the method used, the following requirements apply² to sex determination in the egg:

• Sex must be determined before the 13th day of incubation to avoid causing pain to the embryos
• No adverse effects on the hatch rate
• High reliability in sex determination
• Rapid determination, to ensure high throughput in the hatchery
• Cost-effective, to ensure the procedure can be implemented economically
• Possibility of using the sorted eggs for further processing  
• Public acceptance must be ensured

The methods used here include endocrinological and molecular biological techniques, sex determination via spectroscopy, and an AI-supported MRI method.

SELEGGT was the first company in Germany to bring its method to market. As a result, the first eggs from laying hens whose sex had been determined using the endocrinological method were⁵ marketed under the ‘Respeggt’ label as early as 2018.  PL⁹ANTegg followed suit at the end of 2020. The molecular biology method is used to select hens whose eggs are sold through the discount supermarket chain ALDI. Since 2022, Aldi has only sold shell eggs from hatcheries where sex determination is carried out in the egg, thereby avoiding¹⁵ the killing of male chicks. The Cheggy spectroscopic method from A¹⁰AT, as well as the MRI- and AI-supported method from ORB¹³EM, are both used¹⁶ by the Lohmann hatchery for in-ovo sex determination. In Germany, the endocrinological method, hyperspectral measurement technology and the MRI-supported method are therefore currently in use^{7,10,14,15,17}.

Once the sex of the embryos has been determined, the incubation process for eggs containing male embryos is terminated immediately after sorting, regardless of the method used. The hatching eggs are then crushed and the resulting ‘male mix’ is stabilised. This is subsequently stored under refrigeration and regularly supplied as CAT 3²³ material, i.e. low-risk animal material.

In recent years, various methods have been successfully established that allow the sex of chicks to be determined with a high degree of accuracy whilst they are still in the egg. These methods are applied before the 13th day of incubation, meaning that the chicks do not experience any pain during the sex determination process. The requirements of the Animal Welfare Act have thus been successfully implemented. Consequently, chick culling no longer takes place in German hatcheries. Nevertheless, none of the methods currently achieves 100% accuracy, meaning that the rearing of young cocks will continue. 

Further information on young male chickens can be found in the specialist article ‘Rearing young male chickens – a genuine prospect or a stopgap solution?’.

Furthermore, most organic associations do not regard sex determination in the egg as a suitable alternative, as this merely postpones the killing of male chicks to an earlier stage. Instead, they advocate the increased use of dual-purpose breeds to counteract selective breeding for meat and egg production. The rearing of young cocks is also widespread.

It remains to be seen to what extent other methods, such as that developed by the Israeli company SOOS, will be further developed and whether they will gain a foothold on the German market.