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More counterintuitive chicken nuggets January 29, 2010

Posted by Angelique in Animal welfare.
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Photos of farm animals piled practically on top of each other in confinement can turn the stomachs of even the most inveterate carnivores. We can relate to the horrors of overcrowding. Where it might be hard for humans to imagine how much it bothers chickens to have the tips of their beaks cut off, or how much pigs miss rutting around in the dirt, or to what extent cows would prefer to feel the sun on their backs instead of being inside a barn, we don’t need quite such a leap of the imagination to sympathize with animals who are packed together so closely that they are constantly straining against each other to move. The notion of a chicken enclosed so tightly that it doesn’t even have room to stretch its wings seems to us ghastly, as ghastly as people being crowded so tightly into a cell that they cannot lift their arms.

 Which is why the results of a 2004 study* of meat chicken welfare are so surprising. First, a little background on the study for those of us who are skeptical of scientists’ motivations (rightly so, given the perverse incentives created by the hot pursuit of research funding). The lead researcher on the study is Marian Stamp Dawkins, an Oxford professor specializing in animal behavior who has written extensively of the need to better define, measure and protect animal welfare. Among animal welfare advocates, she is perceived to be one of the “good guys.” She and her team studied the determinants of chicken welfare in 2.7 million birds raised by ten major producers in the UK – a huge sample. They measured welfare using behavior – including walking ability and engagement in natural activities like preening and dust bathing as well as aggressive actions like pecking other birds – in addition to overall mortality rates and levels of corticosterone, a stress hormone, in bird manure. All in all, a very comprehensive approach.

What they found was that stocking density – or how closely the birds were packed together – was, although not unrelated to bird welfare, not nearly as important as other factors. What really mattered to chickens were the temperature and humidity levels in their houses, along with the amount of ventilation provided. (Poor showings for these variables caused damp litter and ammonia-soaked air, each of which in turn caused bird health to suffer and corticosterone levels to rise.) Stocking density had absolutely no affect on mortality rates or leg defects, two of the most important welfare markers, although it did negatively impact the birds’ gaits and increased the amount of jostling going on.

So yet again our intuition proves an unreliable guide to the happiness of animals. This doesn’t mean that we shouldn’t advocate that animals in confinement have more space to move around, or even (imagine!) go outside, but it does mean that we can’t assume, because a package of chicken breasts is marked “free range,” that the chickens who originally wore those breasts were happy, or even had a reasonably decent standard of living. Whether they did depends on many other factors which are pretty much invisible to the consumer. Therefore, the consumer has to find someone or something she can trust to be the expert – a farmer, a restaurant owner, a co-op, a certification – and buy from them. Looking for the words “free-range” on the package just won’t cut it.**

*Dawkins et al, “Chicken Welfare is Influenced More by Housing Conditions than by Stocking Density,” Nature, v. 427, January 22, 2004: 342-344.

**Note that the Dawkins study did not analyze egg-laying chickens, so it does not have any bearing on whether free-range eggs are necessarily more humanely raised than standard eggs, which are laid by chickens in cages. Meat chickens (the subject of this study) are never caged; they are housed on the floor of a chicken house, and given varying amounts of room to move around.

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Comments»

1. Eric C - January 30, 2010

Interesting, thanks for the post.


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