Today, we paid a visit to a large slaughterhouse in Flanders, where laying hens from the Netherlands, France, Germany and Belgium are processed. Our aim was to observe the measures in place to prevent heat stress and to raise concerns about the containers in which part of the hens are transported. After a productive discussion, we were given access to observe the lairage, stunning, and bleeding areas. Below, we summarise our key observations and conclusions.
Excellent lairage: strong ventilation and pad-cooling
Hens often have to wait several hours before slaughter. Thanks to pad-cooling, powerful wall-integrated extraction fans, and darkened skylights, the temperature inside the lairage remained comfortably cool – several degrees lower than outside. The cool air was extracted from the lairage and blown out of the building. On the other side of this wall, a canopy had been installed to channel the cooler air through any waiting trucks. However, the slaughterhouse indicated that trucks are rarely left waiting outside, especially not during hot days. In the vehicles present during our visit (all inside the lairage), we observed no signs of heat stress. In our view, this lairage sets a strong example for other slaughterhouses.


Transfer to the stunner: quiet and low-stress
The crates were fully automatically destacked and conveyed to the CO₂ stunner. This process generated minimal noise or movement. The hall was completely dark, with only dim blue lighting. The hens remained calm throughout and showed little to no signs of stress.
CO₂ stunning
The hens were stunned using gradually increasing concentrations of CO₂ while still inside the crates, avoiding physical handling by staff and thereby significantly reducing stress. The viewing windows were somewhat fogged or dirty, making it difficult to assess the stunning process in detail. As far as we could see, there were no severe aversive reactions – though stress cannot be completely avoided when using CO₂, an inherently aversive gas. The slaughterhouse promised to consider cleaning or replacing the windows for better visibility. According to staff, CO₂ levels are adjusted per flock.
Concerns about containers
Part of the laying hens arrive in containers instead of crates. Eyes on Animals is concerned about these systems, as their drawers are very low and deep. During inspections, we’ve observed that hens must be thrown in horizontally to reach the back. Since hens naturally flap and move during such stressful handling, collisions with the edges of the drawers are highly likely.
Laying hens – who are much more active than top-heavy broilers – often attempt to move forward again in an effort to escape the drawer. They then have to be pushed back into a drawer that offers very limited headspace, which increases the risk of stress and impact injuries. Due to the large drawer openings, limited headspace, and the birds’ natural escape instinct, it is also difficult to keep them inside and to close the drawers without the risk of trapping body parts. These concerns have also been reported to us by poultry catchers.
The slaughterhouse pointed out that containers do allow for better visibility of the birds (for welfare checks) and better ventilation in the lairage, since they can be offloaded and spread out. Crates, by contrast, often remain stacked on trucks, where airflow and visibility – particularly in the middle stacks – are more restricted. While we acknowledge these advantages, we believe the container design nevertheless urgently needs to be improved to reduce stress and injury during loading. Potential solutions include higher drawers and partitions to help prevent escape behaviour. Positive experiences have already been reported with the use of partitions >>
Positive: fewer toe injuries
A promising development is that the slaughterhouse has introduced new drawers with rounded inner edges, which help prevent toe entrapments. The older versions are gradually being phased out.

We thank the slaughterhouse for their openness and trust. We greatly appreciated the opportunity to observe the full process and to exchange ideas about potential improvements. We were impressed by the steps already taken to reduce animal stress – it is clear that much thought has gone into the system. We hope the slaughterhouse will also be willing to re-evaluate the container design in light of our visit.