For years, the conventional thinking has been cage-free eggs are laid by healthier chickens, and as a result, the practice has become more widespread. Last month, IKEA and SeaWorld opted to serve only cage-free eggs, and the average egg consumer might even picture green pastures and fluffy, full-feathered hens as she picks up a dozen cage-free brown eggs at the grocery store. After all, that's the image on the actual egg cartons. However, cage-free doesn’t mean organic, and the typical cage-free farm doesn’t resemble this imagined utopia. Although few would argue that chickens shouldn’t be able to spread their wings and walk around a bit, there's a debate over whether the cage-free method is truly optimal for both hen health and food safety.

In 2008, California voters voted on Proposition 2, which asked if consumers wanted their eggs to come from chickens who could “stand up, lie down, turn around, and fully extend their wings.” And put like that, how could anyone say no? The vote prompted large farms in California to start producing exclusively cage-free eggs. Today, an op-ed in the California Aggie cited a study by UC Davis professor of animal science Dr. Frank M. Mitloehner that claims the reality of the cage-free methods used at some farms is likely not what voters expected when they expressed a preference for cage-free eggs.  

Prior to Prop 2, big egg producers in California used one of two methods of poultry husbandry: conventional cages, in which chickens are housed in—you guessed it—conventional cages, or enriched cages, in which chickens are housed in larger cages with nesting boxes and scratching posts. In contrast, cage-free chickens roam free in an enclosure and lay eggs in manure. Problems arise when cage-free enclosures are built like single, enormous, indoor cages, some housing up to 200,000 chickens

According to the study, cage-free systems cause higher daily concentrations of ammonia and an increased concentration of dust than conventional cages and enriched cages. More alarmingly, these cage-free eggs pose a higher risk of pathogen ingestion. The fact that eggs are laid in manure means that they are exposed to salmonella, more so than eggs laid in and collected from cages. Plus, cage-free hens, while able to spread their wings and move around, are not necessarily in peak physical condition. Hens in the cage-free systems Dr. Mitloehner studied had lower egg counts, higher death rates than birds in other systems, and high rates of pecking and cannibalism between the birds. This last problem is directly caused by a lack of distinct flocks in over-crowded cage-free systems—chickens need to establish pecking order to peacefully coexist. 

So, short of becoming a vegan, what’s an omelet-lover to do? As cage-free eggs become de rigeur—Massachusetts plans to vote on a measure that would mandate cage-free eggs this November—it will be even more important for consumers to carefully read egg cartons to make sure conditions at the cage-free farms that produce those eggs aren't of the overcrowded, indoor variety. Those free-roaming chickens on green pastures are out there somewhere.