Faster, cheaper, sicker

Health problems arising from over-selective breeding of chickens

source: Joyce D'Silva
New Scientist no 2421, November 15 2003 p19

The consumption of chicken broilers worlwide has risen to 49 billion from under 8 billion in the 40 years to 2003, while the time taken to grow chickens to some 2 kilos has dropped to 41 days from almost three months in the three decades to 2003.

Problems can arise in particular from very selective breeding used to produce fast-growing chickens. Compassion in World Farming aims to end this problem through seeking a judicial review of British government policy on selective breeding.

The gene pool of chickens is narrowing. Three companies account for 98% of meat chickens and their descendents world wide. Too-rapid growth can lead to skeletal problems, and as many as 20% of birds may suffer from consequent lameness. Lame chickens choose to eat feed with painkillers, and this helps them to move more normally, according to researchers from the University of Bristol, England. Liver and heart problems are also associated with too-rapid growth. The diets of fast-growing chickens are restricted, when they are not slaughtered at an early age, but instead kept to their breeding age of 20 weeks, since mortality rates are high if these chickens are allowed normal rations. This dietary restriction leaves the chickens chronically hungry. This contravenes a 1998 European Union directive that states that animals should not be farmed of they cannot be kept without health or welfare problems linked to the animals' genotypes.