July 23, 2007

Study says hens feel the same stress whether caged or roaming free

Australian researchers, through assessing the chickens' stress hormones levels, have said that chickens feel the same level of stress whether they are caged or roaming free.

The researchers measured the levels of Corticosterone in eggs from free-range and caged hens. The hormone is produced in response to stress or fear. Results showed that the levels of this hormone in both free-range and caged eggs were very similar.

According to Jeff Downing, at the Sydney University, free-range hens suffer stresses that battery hens do not have to deal with.

Hens with no cover over their heads have to worry about predators, Downing said, adding that hens can be frightened even by shadows over them. Free-range hens are also exposed to manure-borne diseases and parasites. Moreover, unregulated temperatures outside are also stressful to hens, he said.

The study comes as more consumers are buying free-range eggs in the belief that it provides more welfare to chickens. The EU is also phasing out eggs from caged hens in the next few years. 

However, the research is not without its detractors, notably from the SPCA. Julia Wrathall, head of the RSPCA's farm animal department, said the research flies in the face other studies that have suggested that caged birds suffer more than free-range hens.

The RSPCA believes battery cages are unacceptable because they do not satisfy the hens' basic behavioural and physical needs, she added.