Low Atmospheric Pressure Stunning (LAPS®) is a modern, welfare-conscious alternative to traditional poultry stunning methods. But how exactly does it work? Let’s take a closer look at the science behind Low Atmospheric Pressure Stunning.
How LAPS Works – The Less Scientific Bit…
In a LAPS® system, birds remain in their transport crates inside a sealed chamber. The system then gradually reduces atmospheric pressure over a controlled time period, lowering the oxygen concentration in the air. As oxygen levels drop:
- Hypoxia (oxygen deprivation) sets in gradually.
- Birds lose consciousness smoothly without signs of distress.
- Death follows while unconscious, ensuring a humane process before slaughter.
How LAPS Works – With a Bit More Science Thrown In
Beyond its humane framework, the science behind LAPS® is well-substantiated through rigorous physiological and behavioural research.
The LAPS® system executes a precise decompression sequence over approximately 280 seconds. Behavioural cues emerge around 50 ± 30 seconds after the cycle start, followed by loss of posture—indicating loss of consciousness—at approximately 80 ± 18 seconds, and complete motionlessness occurs around 199 ± 21 seconds.
Neurophysiological data reinforce the smoothness of induction: EEG recordings from broilers reveal a sharp rise in slow-wave (delta) activity within just 10 seconds, peaking by 30 seconds into the cycle; heart rate steadily declines (bradycardia), and critically, there are no heart rate increases before loss of consciousness—suggesting the process is non-aversive.
Additionally, comparative welfare assessments by the European Food Safety Authority (EFSA) have assigned Low Atmospheric Pressure Stunning the lowest median welfare hazard score among common methods—3.5 for LAPS® versus 7 for gas and 10 for electrical water bath stunning—underlining its superior welfare profile.
Collectively, these findings demonstrate that LAPS® induces unconsciousness swiftly and painlessly through controlled hypobaric hypoxia, with measurable physiological markers confirming minimal distress and maximum consistency across every cycle.
The entire sequence is carefully monitored and controlled through a programmable system, ensuring consistency in every cycle.
Physiological Responses
Studies have shown that birds subjected to LAPS® exhibit:
- Minimal pre-stun stress indicators (e.g., reduced wing flapping, vocalisation)
- Predictable physiological responses leading to unconsciousness
- Rapid onset of unconsciousness without pain perception
- Minimal risk of physical injury compared to electrical stunning methods
How It Compares to Other Stunning Methods
| Feature | LAPS® | Electrical Water Bath | Gas Stunning |
| Handling Stress | Very Low (no shackling) | High (live shackling) | Low |
| Consistency | Very High | Variable | High |
| Animal Welfare Impact | High (gradual hypoxia) | Moderate (physical shock) | Moderate-High |
| Staff Safety | High (no live handling) | Lower | Moderate |
Backed by Research
Multiple peer-reviewed studies and assessments by animal welfare authorities have validated Low Atmospheric Pressure Stunning as a humane and reliable method of stunning. Regulatory agencies have recognised it in several countries and is increasingly seen as a progressive welfare improvement for poultry processing plants.
In short, LAPS® represents a scientifically backed, humane alternative that supports better welfare outcomes for both animals and processing teams.