The poultry industry argues that bigger chickens means that fewer chickens need to be killed to produce the same amount of meat. But what effect is this extra mass having on the chickens themselves?
Martin Zuidhof, one of the authors of the study acknowledges that with greater size comes health problems for chickens.
"Twenty-five years ago was probably the low point in the industry in terms of negative consequences of selection," he told CTV News. "There were metabolic disorders, heart attacks, just difficulties that were associated with rapid growth."
But according to Paul Shapiro, Vice President of Farm Animal Protection of The Humane Society of the United States, that problem is far from solved.
"Chickens in the meat industry are sentenced to a lifetime suffering because of genetic manipulation that forces them to grow so rapidly," he told The Dodo. "All you need to do is go look at a shed of broiler chickens more than a month old. Most have difficulty walking and often collapse under their own weight."
Chickens Used for Meat
Every year, 9 billion chickens are slaughtered for meat in the United States. Called “broilers” by the industry, these curious, social birds are treated simply as production units, selectively bred and fed for abnormally fast growth without consideration for their well-being. The resulting large size contributes significantly to suffering, disease, and early death.
- Chickens raised for meat are selectively bred to grow to “market weight” at an alarming pace. In the past 50 years, the amount a chicken used for meat grows each day has increased by more than 300%.
- Chickens in the meat industry typically spend their lives confined to warehouse-like buildings, each packed with as many as 20,000 chickens. On average, the space per chicken is only slightly larger than a sheet of letter-size paper. This crowding can result in scratches and sores from the birds being forced to walk all over each other.
- A 2006 study found that 55% of uncooked chicken purchased from supermarkets contained arsenic, which is known to cause cancer in humans. Arsenic is added to the feed of approximately 70% of the broilers raised each year because it is believed to promote growth.
- Since more than one flock is sometimes kept on the same litter before the floor is cleaned, floors can be covered in the waste of tens of thousands of chickens. Excessive ammonia levels that can result from the waste breaking down can lead to health problems for chickens, including difficulty breathing.
- The lights are kept on nearly constantly in the buildings where chickens raised for meat are confined. This can stimulate eating and unnaturally rapid growth and limits the opportunity for chickens to sleep and rest, all of which leads to serious health problems.
- Studies have consistently shown that approximately 26–30% of broiler chickens suffer from difficulty walking because their skeletons have trouble supporting their rapidly growing bodies. This can also lead to deformities and lameness.
- The rapid growth of broiler chickens is often associated with acute heart failure. The hearts and lungs of the rapidly growing birds are not able to effectively get oxygen circulated throughout the body. This problem is the leading cause of death in chickens as they reach “market weight.”
- With bodies taxed beyond belief, chickens who survive their time in production are often slaughtered at just 42 days old. They are still “peeping” the sound of baby chicks when they are killed – even though their bodies have ballooned to the size of giant adult chickens in this short time due to industry practices.
- At the slaughterhouse, there is no law in place requiring chickens to be rendered unconscious before slaughter, and the electrified water bath stunning used has been shown to cause painful shocks before it stuns the birds.