Monoculture

Chickens

A handful of corporations supply most of the breeding stock for all the world’s poultry. Indeed, as of 2000, more than 95% was provided by just four turkey breeding companies, five egg-laying chicken breeders, and five broiler breeder companies.¹⁹²³ Soon, the industry predicts, there essentially may only be three poultry breeders in the entire world.¹⁹²⁴ A single pedigree cockerel can potentially give rise to two million broiler chickens.¹⁹²⁵

Mass consolidation has positive and negative aspects. On the plus side, selection decisions can be propagated around the entire world in a matter of years. If the industry decided to prioritize selection for stronger immunity, in three or four years, practically the entire global flock could be replaced with the healthier, disease-resistant variety. The flip side is that further emphasis on production traits with detrimental effects on immunity are distributed at the same speed.¹⁹²⁶ Another downside is the increasing genetic uniformity of poultry worldwide, which alone may increase the susceptibility of the global flock to disease.¹⁹²⁷

According to the FAO, over the last century, 1,000 farm animal breeds—about one-sixth of the world’s cattle and poultry varieties—have disappeared.¹⁹²⁸ Breeds continue to go extinct at a rate of one or two every week. More than 1,000 breeds—one out of four of all livestock varieties—are presently facing extinction.¹⁹²⁹ The greatest threat to farm animal diversity, according to the FAO, is the export of high-producing breeding stock from industrialized to developing countries that dilutes, or completely displaces, local native breeds.¹⁹³⁰

This erosion of biodiversity has human public health consequences. The American Association of Swine Veterinarians has explained why the genetic bottlenecking created by narrowly focused breeding schemes may be a main reason for the mounting concern over human zoonotic diseases. “As genetic improvement falls into the hands of fewer companies and the trend towards intense multiplication of a limited range of genotypes (monoculture, cloning) develops, there is mounting concern that large populations may have increasingly uniform vulnerability to particular pathogens.”¹⁹³¹ This is the risk posed by any type of agricultural mono-cropping.

We can learn from past mistakes. In the early 1970s, for example, the U.S. corn industry developed “Tcms” corn, a highly profitable strain adapted for large-scale farming. Only after 85% of the nation’s seed corn acreage was covered with the new variety did the industry realize that the strain also happened to be particularly susceptible to a rare form of leaf blight fungus that then wiped out areas of the U.S. corn belt.¹⁹³²

Turkey producers have the option of rearing heritage breeds and so “may be able to improve both disease resistance and the safety of their poultry products,” University of Arkansas poultry scientists point out, “by choosing slower growing commercial lines….”¹⁹³³ There may not be sufficiently slow-growing commercial lines of broiler chickens from which to choose at present, but they could be created if sufficient political will were directed at such a task.

The U.S. poultry industry has started injecting genetic diversity from native Chinese lines of heirloom chickens in hopes of strengthening the immunity of the U.S. flock. “Some of the Chinese chickens have been shown to be very disease resistant,” explains one Hong Kong University zoologist. “Because they have not been under heavy selective breeding, in general their disease resistance is very high.”¹⁹³⁴ Given the inverse relationship between immunity and accelerated growth, though, the industry may not go far enough.

In response to the stalemate between disease resistance and short-term profitability, the industry is experimenting with creating a transgenic “superchicken,” genetically engineered to be resistant to avian influenza.¹⁹³⁵ This is reminiscent of the cattle industry’s attempt to invent mad cow disease-resistant cattle. Might it not be more prudent to simply stop feeding natural herbivores slaughterhouse waste? Prudent, perhaps, but hardly economical. Five years ago, New Scientist editorialized:

[W]hy are animal diseases such a problem in countries like Britain anyway? The answer lies less in the DNA of our cows and pigs and more in our subsidized system of intensive farming and long-distance trading in animals which encourages infections. There is a danger that genetic modification will be used to shore up this system by making farm animals better equipped to survive cramped conditions. Indirectly, it could even help to spread disease susceptibility by encouraging farmers to switch from genetically diverse breeds to high-yield GM [genetically modified] animals drawn from a narrow gene pool.”¹⁹³⁶

Biodiversity is biosecurity. Even the most virulent of diseases typically do not kill all infected individuals, in part due to natural inborn genetic variability. In the wild, natural selection takes advantage of this variation to pass disease-resistant qualities to the next generation.¹⁹³⁷ The diversity in nature tends to ensure that some individuals will survive whatever comes along. Artificial selection for production qualities undermines Mother Nature in two ways, by inbreeding unnaturally elevated egg production and fleshiness over fitness, as well as by reducing the genetic diversity that can act as resistance insurance against present and unforeseen threats of disease.¹⁹³⁸