How to measure suffering? The Welfare Footprint Project investigates

In previous blogs, we’ve discussed the health issues experienced by chickens raised for meat, and why slower growing breeds suffer far less from these. But what kinds of pain do these health issues cause?  

The Welfare Footprint Project investigated the suffering experienced by different commercial breeds of chickens used in the meat industry. They specifically compared conventional fast-growing breeds to slower growing Better Chicken Commitment compliant breeds. 

The Project’s key finding is that adopting the Better Chicken Commitment prevents a huge amount of suffering. Crucially, the most and second-most severe categories of pain are cut by 80% and 65% respectively. However, this only happened when the breed of chicken was switched to a higher welfare breed. Just improving living conditions without any breed change had little impact on suffering. 

What causes of pain were measured? 

The study measured: 

• Lameness 

• Cardiovascular problems (e.g. heart attacks and ascites) 

• Thermal stress (i.e. overheating) 

• Frustration (from sensory and behavioural deprivation) 

• Chronic hunger 

• Welfare harms during stunning and slaughter 

As this isn’t an exhaustive list of the welfare harms impacting chickens raised for meat, the measurements produced by this study underestimate the actual time in pain endured in commercial production. 

The study did not include the following, which are known to have higher incidence in fast-growing birds: 

• Infectious diseases 

• Inflammatory conditions 

• Contact dermatitis 

• Muscle abnormalities

Image: Welfare Footprint Project

Not all pain is equal 

Of course, just measuring time spent experiencing pain alone is not enough to tell the whole story. Pain ranges in severity. That’s why the researchers categorised pain into four types from least to most severe. 

1. Annoying Pain 
   Pain that is clearly felt, but doesn’t disrupt normal behaviours and causes only mild mental disruption. It can be ignored most of the time. Chickens experiencing this kind of pain don’t show physical signs of pain or vocalise that pain. 

2. Hurtful Pain 
   Disruptive pain, which at best can only be ignored for brief periods depending on what else draws their attention. Chickens experiencing hurtful pain can still behave normally, but may struggle to do so, and may do so less frequently or for shorter durations. While experiencing hurtful pain, chickens don’t do things that aren’t immediately rewarding, like dustbathing. 

3. Disabling Pain 
   As the name suggests, this is the kind of pain that makes it impossible to behave normally. It can also be so bad that milder pain or even positive experiences aren’t noticed. Chickens experiencing disabling pain are motivated to move less, to try to reduce this pain. 

4. Excruciating Pain 
   Unable to cope with this kind of pain for even a few seconds, this completely overwhelms the body. Examples of causes of this kind of pain are severe burns or scalding. Chickens experiencing excruciating pain tend to have extremely abnormal physical reactions, like screaming or shaking. Individuals experiencing this kind of pain can’t hide it. 

The study also measured the likelihood that an average chicken would experience each kind of pain from each cause. For example, lameness is far more common than fatal cases of ascites.  

To give a measure of the population-level pain experience, the duration of the pain type caused was multiplied by its prevalence. A condition that causes 10 hours of disabling pain, and affects 70% of the population, could be said to cause 7 hours of disabling pain from this condition in the average chicken. This allows for a more comprehensive comparison. 

What are the most common causes of pain for chickens raised for meat? 

Image: Welfare Footprint Project

The biggest cause of pain in chickens raised for meat is lameness, followed by heat stress. Lameness causes 3.5 times more disabling pain for fast-growing chickens than for slower growing chickens, and 1.5 times more hurtful pain. Time spent in annoying pain caused by lameness is about the same across breeds – this tells us that while slower growing breeds are not immune from lameness, they certainly experience far less pain overall, and suffer less. 

Fatal cases of ascites are comparatively rarer but are the biggest cause of excruciating pain in fast-growing chickens. Affected birds experience a horrific 40 minutes of excruciating pain on average. However, this excruciating pain functionally disappears for slower growing chicken breeds, who are far less likely to experience ascites, fatal or non-fatal. 

How much pain does the Better Chicken Commitment prevent? 

The Welfare Footprint study found that adopting the Better Chicken Commitment in full prevents at least 79 hours of hurtful pain, 33 hours of disabling pain, and 25 seconds of excruciating pain for every single chicken raised under the higher welfare standard.  

In fact, slower growing chickens were found to experience more than 80% less excruciating pain than fast-growing chickens – just a few seconds in their lives. They experience just a quarter of the amount of disabling pain experienced by fast-growing chickens. This is clearly a huge reduction in suffering. 

The slower the growth rate, the shorter the cumulative time in pain experienced over a chicken’s lifetime, regardless of actual lifespan. In other words, a chicken who lives longer and takes more time to reach the same weight as a faster-growing bird will have a lower total amount of time spent in pain.  

Importantly, this study found that changing the way chickens are raised, such as giving them more space or enrichment, has little impact on pain alone. These changes have the best welfare impact when combined with a switch to slower growing breeds.

The study is conservative – meaning the difference could be bigger 

The findings of this Welfare Footprint Project study can be considered as conservative estimates, “representing the minimum time in pain expected to be averted with implementation of the BCC and similar standards”.  

As explained earlier, the study did not measure all significant causes of pain in chickens raised for meat. For example, skin conditions are not considered by this study. We know that slower growing chickens are far less likely to be affected by these conditions. 

In other words, this study shows the absolute minimum reduction of suffering produced by switching to the Better Chicken Commitment. 

You can read the study in full on the Welfare Footprint Project website here – including interactive charts which show more detail.