What Makes a Better Broiler Chicken - Better Chicken Project - Global Animal Partnership

Today, nearly 90% of the 68 billion broiler chickens produced annually are a strain of Cornish Rock cross, a fast growing and highly efficient broiler chicken. The fast growing, conventionally reared broiler chicken weighs about 5 lbs at 5 weeks of age, and nearly 8 lbs at 7 weeks of age.

Because of their heavy weight and fast growth rate, broiler chickens may experience poor welfare. They can develop significant problems such as high mortality, difficulty walking or painful skin lesions. Small-scale research studies have suggested that slower growing strains of broiler chickens have better welfare than conventional strains.

What does “animal welfare” mean?

For the chicken, good welfare means that the animal is healthy, able to do the things it wants to do, and experiences minimal stress, pain and frustration.  G.A.P. defines animal welfare according to 3 main pillars:

  • Health & Productivity – the animals are healthy and productive with good quality feed and water, shelter, and free from disease, illness and injury (and, of course, treating any animals that get sick).
  • Natural Living – the animals are raised in environments that allow them to express their natural behaviors – both indoors and outdoors
  • Emotional Well Being – the animals are raised in environments that provide them the ability to be inquisitive and playful and minimize restlessness, frustration, stress and pain, as much as possible.

In order to satisfy the three pillars of good welfare above, you need proper farm management of the birds, a healthy diet with no antibiotics, hormones, or animal by-products, a healthy environment that encourages the birds’ natural behaviors, and, lastly, good genetics. G.A.P.’s 5-Step® Animal Welfare Certification standards outline specific requirements related to all of these categories – management, diet, environment, and even breed – but issues still remain that deserve more attention. That’s why G.A.P. helped secure funding for the Better Chicken Project study conducted by the University of Guelph – to better understand the impact of broiler chicken genetics on the animals’ overall welfare, and how we can use this data to reinvent the modern day broiler.

As we mentioned in the original blog “Why should you care about broiler chicken welfare?“, in this comprehensive, multifactorial broiler chicken research study conducted at the University of Guelph, scientists compared the welfare of 16 strains of broiler chickens with different growth rates to determine if growth impacts welfare. In the research study, the broiler chickens were all housed, managed and fed the same way according to G.A.P.’s 5-Step® Animal Welfare Standards for Chickens.

What does it mean to be a “slow-growing” broiler (vs. “fast-growing”)?

There is no standard definition of a slow growing broiler chicken. Various government and animal welfare organizations require broilers within their programs to be slower growing than conventional strains (taking anywhere from 3 to more than 50 extra days to reach 5 lbs). The team at Guelph used strains with a range of growth rates, including strains that would take anywhere between an extra 5 to 75 days to reach the same body weight as conventional, fast growing strains reach in about 35 days. Most of the strains in the Guelph study required an extra week or two to reach the same body weight as a conventional strain.

Strains of chickens used in Guelph study, listed in alphabetical order, and the number of days they need to reach 5 lb

Is slower better for animal welfare?

It is important to consider a couple of facts around the term “slow growing”. Slower growth is not necessarily an indicator of better welfare. Growth rates can slow down due to poor diet, overcrowding or diseases, all of which lead to poor welfare. It is critically important not to replace one welfare problem with another.

Conventional broilers of the 1950s and 1960s were also slower than the conventional broilers used today, but they were inefficient and had high levels of mortality despite the regular use of antibiotics in their feed. Over the past 60 years, improvements in veterinary care, housing, and management (due to organizations like G.A.P. positively creating standards for animal welfare) have reduced the average mortality rate. For example, G.A.P. animal welfare standards require, among many other things, the use of a high quality diet to meet the nutritional needs of the animals, humane animal handling and limited transport, and a safe and enriched environment so that chickens can “be chickens”.

As we mentioned earlier, the research team at the University of Guelph used a multifactorial approach, as no single factor can tell us everything we need to know about broiler welfare.

The scientists designed their study to examine the following factors across all of the strains and their corresponding growth rates:

  • Physical Behavior – things such as being active, using enrichments and performing a variety of behaviors,
  • Outward signs of pain, stress, or frustration – this includes things like lameness, inactivity and immobility,
  • Health – this includes things like organ and bone development – biological markers of disease and mortality, and
  • Yield and Meat Quality – things like muscle issues resulting in “woody breasts” and white striping, which impact overall yield and quality, as well as the animal’s health.

We’ll be publishing blogs addressing all of the key categories of the study and what the data is (and is not) telling us. G.A.P. will also be forming a Technical Working Group to determine next steps for how to develop and incorporate further specifications around breed into our G.A.P. Animal Welfare Standards. Stay tuned for important insights in this multi-part blog series.