Hazards On The Bird Killing Floor

The killing of millions of birds for human consumption takes place in slaughterhouses or during on-farm slaughter all over the world. In this extensive study, a large group of researchers, including the European Food Safety Authority (EFSA), assessed processes included in slaughter, from the arrival of birds in containers until their very death. The following are some of the findings presented in the publically-available scientific opinion report.

Hazards for birds can arise even before they get to the stunning section of the factory. Pre-stunning processes include: arrival, unloading containers from trucks, lairage (essentially waiting time on the floor in between processes), as well as handling and  removal from the containers.

Here, the authors cite studies showing that extended times without feed, heat/cold stresses and struggles during handling adversely affect welfare as well as meat quality. Some people find it surprising, but we must realize that birds often are deprived of food and sometimes even water before even being put to transport, not to mention the variable conditions the animals are submitted to within the containers.

Large, modern animal factories typically employ electrocution as the means for stunning birds prior to slaughter. The most obvious hazards here arise from the fact that ensuring adequate electric shock to render multiple birds unconscious simultaneously is challenging to say the least. Studies show that stunning efficiency varies greatly, in some cases exhibiting abysmal performance, only properly stunning 4 of 10 birds. Other confounding factors include runts (small birds) missing the stunner, while injured birds would experience extra distress and pain upon shackling. In fact, out of the identified hazards, most are related to stunning and bleeding.

Normally, slaughterhouse employees would inspect each bird before and after stunning to ensure their wellbeing. However, facilities where the production lines are fast (more than 2 birds are killed per second), do not allow for any human intervention. Moreover, some religious traditions in Europe require the use of low currents in waterbath stunners as such stunning conditions cannot result in cardiac arrest, allowing for the preferred bleeding out of live animals. In general, the application of higher currents leads to a conflict between higher animal welfare and poorer meat quality. The alternative high throughput method – gas induced loss of consciousness, also comes with its risks of failure, leaving animals to suffer upon slaughter when the gas concentration is too low and causing severe health issues when it is too high.

Other stunning methods, employed in smaller operations, include bolt gunning, percussive blows (head hitting), manual cervical dislocation (neck breaking) and decapitation. The methods are much more manually intense and prone to human error, be it due to lack of expertise or fatigue. They are usually recommended only when no other method is available. The inefficient application of these methods expose the birds to slower, painful suffering due to blunt force trauma or asphyxiation. 

All in all, the researchers highlight that some hazards are inherent to stunning methods and thus cannot be avoided. A good example of this is the necessity to shackle and invert birds before electrocuting them in a waterbath. Other hazards, however, originate from suboptimal application of the chosen method. This typically includes rough handling or using incorrect equipment settings by unskilled staff. Indeed, 29 out of the 35 identified hazards, a whopping 83% were caused by staff. 28 of them were attributed to a lack of appropriate skill or fatigue.

Overall, the researchers highlight ten welfare consequences that the birds can be exposed to during slaughter: consciousness, heat and cold stress, prolonged thirst and hunger, restriction of movements, pain, fear, distress and respiratory distress. The authors assessed possible corrective and preventive measures and highlighted 11 measures to correct some of the hazards. Management was shown to be critical in welfare issue prevention. Namely, slaughterhouse workers need to inspect the condition of the birds at each phase of slaughter. In particular, emphasis is placed on: inspection and maintenance of containers, staff training and rotation, appropriate setting and use of equipment, and ensuring a back-up stunning method is ready at all times.

For animal advocates and other effective altruists alike, the report is a crucial resource for information about  welfare issues that the farmed animal industry can be pressed to improve upon. Successes in alleviating the animals from any of the reported hazards would lead to the improvement of countless animals’ lives. A key takeaway is that the industry seems to undermine the importance of the individual: both in the case of the animal to be killed, where he or she is not monitored along the way, and the floor worker, where managers often fail to provide the necessary training or ensure that he or she rests sufficiently.