Anyone who has ever paused in front of the massive egg refrigerator in a grocery store has likely noticed the significant difference in price between the various cartons. The math on some characteristics like cage-free or free-range can be a little dicey, varying from producer to producer and farm to farm. But there is one rule of egg-buying that generally remains the same: brown eggs cost more than white eggs. But why? If you’ve ever wondered, read on. Om-e-lette you in on a little-known secret.
The price gap between white eggs and their more expensive brown cousins isn’t due to simple aesthetic preferences. And it’s not because brown eggs are somehow more nutrient-rich or lower in cholesterol either. In fact, brown eggs are no healthier for you than white eggs at all.
It turns out that the higher cost of brown eggs has to do with how the eggs are formed within the hen. All eggs get their start within a hen’s single functional ovary when it is released as a yolk. The yolk is then carried into the infundibulum, the first part of the oviduct. If a hen mates with a rooster, this is where fertilization takes place. If there is no sperm present here, the yolk then journeys on to the magnum, where the Albumen (what we commonly call the egg “white”) is formed around the yolk. After one more stop in the isthmus, where further membranes are deposited around the albumen, the egg advances to the uterus.
A hen’s uterus is also called her shell gland pouch. This is where all of the hardening happens. Over the course of a 24-hour stay here, the shell is created around the soft innards of the egg in a process that sees layer after layer of white shell effectively “painted” on by the gland pouch. The eggs spends the longest amount of time here in this stage by far.
Once the shell is formed, a white egg-laying hen will experience uterine contractions, and eventually lay the egg. But for hens that lay brown eggs, there’s an additional step before the egg can be released. You see, all hens create white egg shells in the shell gland pouch. The inside of a brown egg is, afterall, a pristine white. But hens who lay brown eggs undergo a paint job of sorts in the final hours that the egg sits in the shell gland pouch.
Creating this brown pigment on a daily basis takes additional energy and nutrients, and therefore more food. Hens that lay brown eggs have to eat more feed than hens who lay white eggs. Supporting a farm full of brown-egg chickens costs a farmer more money than if he were to support an identical number of white-egg chickens. This added cost is the very reason that white eggs rose to ubiquitousness in the U.S., and throughout much of the world, in the first place.
Brown eggs returned to prominence largely through marketing. A decade or two ago, brown eggs’ very color seemed to exist in protest to the industrial egg farming complex that favored white eggs because of their inexpensiveness to produce. A carton of brown eggs seemed to communicate to the buyer that the chickens had been offered a better life, or had been loved even.
As egg-buyers, finding that narrative convincing, began to favor brown eggs, large scale chicken farmers adapted by rearing brown egg-laying chickens. The additional feed costs – at the scale of hundreds of millions of hens in the U.S. alone – are then passed along to consumers by charging more for a carton of brown eggs.
And there you have it! Brown and white eggs are nutritionally identical. The only reason brown eggs cost more is because all that brown pigment takes more food, and more money, to produce.