AR-News: Housing vital to chicken welfare
wolfcrest at hotmail.com
Thu Jan 22 19:40:38 EST 2004
Housing vital to chicken welfare
By Paul Rincon
BBC News Online science staff
The chickens are very sensitive to their environment
Chickens that are commercially farmed for their meat will suffer more
through bad housing conditions than through overcrowding, experts have
The European Union (EU) is planning a limit on stocking densities, but the
latest study suggests other measures could improve the birds' welfare.
The moisture of the birds' litter and ventilation levels were found to be
the most important factors for well-being.
Details of the research are published in the scientific journal Nature.
"If you give the birds a reasonable environment, you can mitigate some of
the effects of stocking density that you might find in less good housing,"
Dr Marian Stamp Dawkins, a zoologist at the University of Oxford, UK, told
BBC News Online.
About 70% of the UK broiler chicken industry was involved in the study, Dr
Dawkins added. Ten companies in total took part, making it the biggest study
of its kind.
As part of their participation in the study, the firms were asked to keep
chickens at different stocking densities - the measure of how crowded a
chicken house is - so the scientists could measure the effect of this factor
on chicken welfare.
Those correlations point to further research, rather than being definite
conclusions in themselves
Dr Marian Dawkins, University of Oxford
The level of moisture in the birds' litter and the concentration of ammonia
had a significant effect on chicken health. These factors are both related
to an increased incidence of problems with the chickens' feet and legs - an
important measure of their health.
Temperature fluctuations and overall humidity can also have a strong
influence on the animals' welfare.
Unexpectedly, ammonia was associated with lower bird mortality, but it was
also correlated with higher levels of stress hormone in the birds.
However, the research does not assess the relative importance of these
"Those correlations point to further research, rather than being definite
conclusions in themselves," explained Dr Dawkins.
"If you do the ventilation and air circulation right then you're not
compromising their well-being. To the human eye it looks very crowded, but
in terms of animal well-being I don't think they're being compromised,"
commented Professor John Feddes, an expert in animal housing, from the
University of Alberta, Canada.
But the RSPCA dismissed the conclusions of the report.
"Given that at slaughter a broiler weighs two to three kilograms, we are
looking at around 23 birds crammed into a square metre in some of these
sheds by the end of their lives," said RSPCA senior scientific officer
Caroline Le Sueur.
"That provides less space than for battery hens."
Dr Dawkins emphasised that stocking density is still an important factor in
The report found that when chickens were housed at high densities, they
jostled more and also grew more slowly than animals with more space.
But more obvious measures of bird welfare - such as the number of birds that
die, are culled as unfit and show leg defects - were not affected by
Dr Dawkins describes the findings as surprising, because stocking density
was always thought to be the major welfare factor for chickens.
"[The EU] had been open to the idea that stocking density might not be the
only thing to look at and that you might be able to specify certain
environmental factors which were also important," she told BBC News Online.
"And I'm just hoping that they're going to take that on board."
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