Pollutants incubating in free-range eggs

If a chicken could choose its coop, there's little doubt it would prefer one with plenty of space, sunshine and good grub. Most people would agree it's more humane to raise animals in their natural environment, without artificial hormones, cages and unsanitary conditions. When it comes to our own health, however, free-range isn't necessarily best.

A recent study from Taiwan found that eggs from free-range chickens contained nearly six times higher levels of dioxins than conventional eggs. Dioxins, a typical by-product of burning waste, have been linked to cancer and reproductive issues in humans. We no longer live in a world where we can dip our hands in a lake to drink or till the land under our feet without exposing ourselves to the harmful chemicals in our water and soil. The diet of caged chickens can be tightly controlled, providing a perfect balance of nutrients and supplements, though their quality of life is questionable. More freedom, on the other hand, appears to expose chickens to more environmental pollutants. Which should come first: the chicken or our health?

Previous studies have found no difference between free-range and caged chickens in terms of infectious disease. In 2004, a USDA study found salmonella in a quarter of all chickens in the market - caged, free-range and organic alike. The researchers also found no difference in nutritional value between free-range eggs and conventional eggs.

The researchers in Taiwan cautioned that their study sample was small and conducted in a heavily populated area, near municipal incinerators. Even so, it's clear that care should be taken to raise animals on toxin-free land. Otherwise these toxins can be magnified through the food chain, moving from soil to plant to animal to human. Chickens don't roam far from their roosting area either, so the ground can quickly become depleted of nutrients, mud-packed and covered in feces. Some farmers solve this problem by periodically moving enclosures from one pasture to another.

Mainting genetic diversity may also help. In 2008, researchers from the United Kingdom found a link between healthy chickens and a diverse population. They concluded that a free-range lifestyle isn't a major source of infection, contrary to the concerns of non-organic poultry farmers.

The term "free-range" can be controversial because it doesn't distinguish between a wide pasture and dirty gravel. As long the birds are allowed outdoor access, with no specific length of time or ease of gaining access to the outdoors, the USDA considers them free-range. This leaves consumers essentially in the dark when trying to determine what kind of life their chicken led. The definition also only applies to chickens raised for meat, not eggs.

Those who truly care about the welfare of animals probably won't be eating them anyway. Those who do eat chicken and care about their health should acquaint themselves with local farmers, make sure the animals aren't being exposed to unnatural or harmful chemicals and generally avoid poultry in areas that may be contaminated by industrial run-off and other waste.