Eggs laid from hens kept in cage-free or pasture raised environments aren't significantly more nutritious than regular eggs laid by hens kept in a cage, chicken researchers and dietitians say.
"The bottom line is there is no difference," poultry specialist Darrin Karcher said of cage-free eggs verses cage eggs. Karcher helped build a chicken research facility at Michigan State University and now teaches at Purdue University.
Cage-free eggs are laid by hens that usually live in open barns and have access to move from levels to the floor. Hens in a cage system do not have access to the floor and live entirely in a cage.
Cage-free eggs usually cost $1 to $2 more than cage eggs.
Pasture-raised hens produce eggs that have slightly more Vitamin E and omega-3 fatty acids compared to caged hens, but in levels that aren't significant, dietician Jessica Crandall, spokeswoman for the Academy of Nutrition and Dietetics, said.
"There's not a lot of nutritional difference when we look at cholesterol, fatty acids and vitamins," Crandall said.
You can get additional Vitamin E and omega-3 fatty acids in much higher quantities elsewhere, she says.
Nuts have Vitamin E and certain fish have higher levels of Omega-3 fatty acids. Crandall recommends salmon, tuna, mackerel and hearing.
Pasture-raised hen farmer Cathy Doyle says her family thinks eggs from pasture-raised hens taste better.
"They have a stronger flavor," Doyle said. "They have a nice bright yoke."
Crandall agrees that the eggs may taste different, but she says that shouldn't be confused with more or less healthy.
"Sometimes we perceive color as healthier, Crandall says. "It's personal preference whether someone likes one type of egg more than another."
When it comes to brown verses white eggs, she says there is also no nutritional difference.
The color of the yoke in pasture-raised eggs has to do with what the animal eats, Karcher says.
"What it boils down to is that when birds consume grass, insects and other things as they are out pasturing, they pull the color out of what they eat and then deposit it into the yoke," Karcher said.
It doesn't change the nutritional value, he said.
There is one exception when it comes egg nutrition, Karcher said.
"The only documented evidence that there has been a change in the nutritional value of the eggs is with Eggland's Best. They can make the dietary claims that there is a difference between their type of egg verses the conventional egg," Karcher said.
The company says the nutritional change is a result of a special diet hens are fed.
Eggland's Best says its eggs have more Vitamin E, less saturated fat, more Omega-3s, more Vitamin D, Vitamin B10 and lutein.
Lutein helps protect and maintain healthy cells in the eyes, according to the American Optometric Association.