Broilers: Slow and Steady Wins the Race?

Recently, M&S has become the first UK retailer to commit to removing all fast-growing broiler chickens from their supply lines. In the next 12 months, all fresh chicken products will be sourced from slow-growing breeds. Processed chicken products, for example those in ready-made sandwiches or meals, will be sourced from slow-growing broilers by 2026. This announcement comes at a time when animal welfare is very much in the public eye with the launch of DEFRA’s Animal Welfare (Kept Animals) Bill. So what are fast- and slow-growing broilers? What is the difference between them and why is it important?

What are Broiler Chickens?

Broilers, or broiler chickens, are chickens that are bred and reared for meat. While historically chickens would have been reared for meat and eggs, these days there are distinct lineages which are bred for different purposes. Broiler chickens are bred to grow quickly, particularly putting weight into breast tissue. This increases the speed of production and enables industrial scale chicken rearing.

Demand for chicken products is ever increasing.
Demand for chicken products is ever increasing.

Across the world, over 66 billion chickens are slaughtered for meat every year. That is on average 13.6kg per person per year, but can be up to 63kg per year. This varies dramatically with location, as some countries for example the US, eat far more chicken per capita than others. With such a massive industry, there is immense pressure on producers to produce more meat for less money. Growing human population has led to the necessity for affordable and high quality protein sources and this has, in turn, driven the growth of the fast-growing broiler industry.

What are Fast- and Slow-Growing Broilers?

Fast-growing broilers are able to grow to slaughter weight (about 2.5kg) in 35 – 42 days. This means they put on at least 50g per day. In contrast, slow-growing broilers put on less than 50g a day, and are usually slaughtered around 60 days. Commercial layer chickens tend to reach maturity and start laying after around 19 weeks (133 days). They usually weigh around 2kg at this point, but tend to get heavier as they grow up further. As such, they grow much more slowly than broilers.

While fast-growing broilers make up most of the global chicken flock, this does vary according to country. Although 90% of broilers overall in the EU are fast-growing breeds, in the Netherlands and France, around 40% and 24% respectively of birds are slow-growing.

What is the Problem?

Although they are an attractive prospect in terms of economics and world hunger, fast-growing broilers present some welfare issues. Although these chickens grow extremely fast, they do not necessarily grow in proportion. This means that, although the chicken might be putting on muscle and fat, often its legs will not be growing at the same rate. This leads to high incidence of lameness, as the chickens’ legs are just not capable of holding up their body weight. This can be exacerbated by poor litter quality and burns from accumulated excrement on the feet of the birds.

While cages for broilers are illegal in the EU, they are not uncommon in other parts of the world.
While cages for broilers are illegal in the EU, they are not uncommon in other parts of the world.

Heart problems are also a risk for commercial broilers. This is usually the cause of sudden death syndrome and the development of ascites – fluid filled tissues. This is partly due to the genetic basis of high growth rates, but is also due to the way the chickens are fed. High feed density and nutritional intake can cause extreme growth, even in animals which aren’t bred for it, and this can cause bone defects, lameness and mortality.

Behavioural Changes

Fast-growing chickens tend to show fewer natural behaviours than slow-growing broilers and have consistently lower welfare. They don’t explore their environment as much and are much less likely to perch or dust-bathe than slow-growing chickens. Some of this is likely due to decreased floor space, as most fast-growing broilers are raised in intensive conditions.

The regulations surrounding housing for commercial chickens varies with the type of meat produced. Organic and free-range chickens must have a greater minimum floor space and access to more enrichment activities than barn-reared broilers. Cramped and stressful conditions can lead to health problems such as necrotic enteritis. Some differences in health between flocks are due to their environment, as well as their breeding. Often, organic or free-range broilers will need to meet a minimum age before slaughter which is greater than the norm for fast-growing breeds.

Why Aren’t Slow-Growing Broilers More Common?

Slow-growing and free-range broilers require much more space than their barn-raised counterparts.
Slow-growing and free-range broilers require much more space than their barn-raised counterparts.

Moving from fast- to slow-growing broilers takes effort and investment. Slow-growing birds need more space and more feed. They take longer to reach slaughter weight and so overhead costs for producers are higher. This inevitably results in higher costs for the end consumer. For many producers, it is not economically viable to move to more slow-growing breeds. Demand for cheap meat is high and many people don’t want to or are not able to pay for more expensive meat. Similarly, slow-growing chickens, especially if they’re organic or free-range require more space. As a result, more land is needed to produce the same amount of meat and that can be a challenge where land is in high demand.

That being said, many people care deeply about where the meat they eat comes from and the welfare of the animals. Since 2016, over 200 food companies have committed to meet the standards of the Better Chicken Commitment by 2026. This is a world-wide set of standards for industry practice that covers everything from slow-growing breeds and slaughter procedures to housing requirements and stocking density.