Sunday, 28 October 2012
food for thought
There are two problems: the huge energy input to light and heat the enormous sheds in which most chickens are reared nowadays; and the need to feed all these captive birds, which cannot forage for themselves. The two problems are closely related.
If we focus on the amount of energy that is needed to raise an individual chicken to a size where it can be eaten, it becomes apparent that the process is inefficient, because in addition to the parts of the chicken that can be eaten, energy has gone into producing feet, feathers, a head, blood and guts, which are essentially waste by-products. These can of course be reprocessed, but that requires yet more energy.
How would this reprocessing be achieved in nature? The animal kingdom divides neatly into two: herbivores eat plants, and carnivores eat the herbivores. But there is a third category, the detritivores, whose function is to clean up the mess left by the other two. Vultures and hyenas are part of this process, but by far the most important member of the clean-up brigade is the humble fly, without which the world would soon be buried under the weight of detritus generated by the twin processes of life and death.
However, it is not the adult fly that carries out this function but its larvae. Adult flies are justly reviled for spreading disease—they vomit on food and transfer contaminants from one food source to another—but this revulsion also extends to its infant offspring. Note that the larvae of butterflies and moths, widely acknowledged to be beautiful creatures, are called caterpillars, a name that has a romantic ring to it, even though the amount of damage they cause to food crops is often considerable. Fly larvae, on the other hand, are known as maggots, an altogether more sinister word and one that is often appropriated as a term of abuse. Yet once the large carrion eaters have had their fill, it is left to legions of maggots to scoff the rest before metamorphosing into more adult flies to carry on the cycle.
What if we could harness this process to deal with the waste from factory farms? This idea might sound far-fetched, but it is already being pioneered on a small but workable scale. The idea originated in South Africa, where chicken waste was routinely left in the open to rot. An astute observer noticed first the huge number of flies that this practice attracted and second the speed with which the waste disappeared.
Industrial trials involving millions of flies and tens of millions of maggots have shown that significant quantities of chicken waste can be consumed in just 72 hours. And this is where the feeding problem alluded to above enters the picture. Currently, chickens are fed fishmeal. Some of this is made from by-catch, unwanted fish species caught in the nets of trawlers fishing for other varieties. However, a lot of industrial-scale fishing, which itself requires huge energy inputs, is solely to produce fishmeal, and particularly worrying is a recent move to start fishing for the tiny crustaceans collectively known as krill to meet the demand from chicken farmers for fishmeal. In other words, having all but destroyed the top of the food chain in the world’s oceans, humans seem bent on destroying the bottom too. A better example of myopia would be hard to find.
However, the maggots that ate the chicken waste in the previous paragraph can be dried and processed into chicken feed that has been given the proprietary name ‘magmeal’. If current trials can be scaled up sufficiently, it should become unnecessary to continue to pillage the oceans in order to feed factory-bred chickens. There is just one tiny problem: would consumers knowingly eat chickens that have been fed on maggots, given their likely revulsion at such things? Well, chickens raised naturally routinely scratch about in the soil for worms and grubs, and this does not appear to deter those consumers who are willing to pay extra for organic chicken. And most people were happy enough to eat beef from cows fed processed sheep’s brains, until, that is, it became apparent that they ran a significant risk of contracting a new variant of Creutzfeldt-Jakob disease.