Nutrition: Free Range vs. Battery Cage Eggs

Eggs, Image Courtesy of Jiggoja,

A number of recent studies have shown that eggs produced by free-range hens are more nutritious than those laid by hens in battery cages.

Eggs have a high nutritional value with a relatively low calorie count (just 70-80 calories each). An egg contains about 6-6.5 grams of protein, and the biological value of egg protein (which indicates the ability of the body to use it) is higher than that of milk, beef, poultry, fish, soybeans, wheat, corn, and rice (Wageningen University, 2009).

The only real nutritional concern with eggs is cholesterol, but because egg whites contain more protein than yolks and no cholesterol whatsoever, those concerned about LDL don’t have to forgo them.

Free Range Hens Produce Nutritionally Superior Eggs

Mother Earth News conducted an egg testing project in 2007, finding that eggs produced by free-range hens compare favourably with those produced by battery cage hens. Eggs from free range hens had up to:

    • 1/3 less cholesterol
    • 1/4 less saturated fat
    • 2/3 more vitamin A
    • 2 times more omega-3 fatty acids
    • 3 times more vitamin E
    • 7 times more beta carotene

The study involved 14 flocks across the United States whose eggs were tested by an accredited Portland, Oregon, laboratory, and the results were similar to those obtained via a 2005 study of four flocks. In addition to the Mother Earth News research findings, there have been a number of other studies showing that free-range eggs are healthier than those produced by battery-cage hens. Findings include the following:

    • Free-range eggs contain 70% more vitamin B12 and 50% more folic acid (British Journal of Nutrition, 1974).
    • Greek free-range eggs contain 13 times more omega-3s than U.S. commercial eggs (Simopoulos, The Omega Diet, 1988).
    • Pasteurized eggs are higher in vitamin E and omega-3s than those obtained from battery-cage hens (Animal Feed Science and Technology, 1998).
    • Free-range eggs are 10% lower in fat, 34% lower in cholesterol, contain 40% more vitamin A, and are 4 times higher in omega-3s than standard U.S. battery-cage eggs, and free-range chicken meat has 21% less fat, 30% less saturated fat, and 50% more vitamin A than that of caged chickens (Gorski, Pennsylvania State University, 1999).
    • Free-range eggs have three times more omega-3s and are 220% higher in vitamin E and 62% higher in vitamin A than eggs obtained from battery cage hens (Karsten, Pennsylvania State University, 2003).

Long and Alterman (2007) attribute the dramatic differences in nutritional content to the fact that free-range hens consume a more natural diet that includes various seeds, worms, insects, and green plants, whereas hens in battery cages have no opportunities to forage and are fed cheap blends of soy, corn, and/or cottonseed.

In addition to having poorer diets, battery cage hens are kept in horrendous conditions, so they live their lives in a state of extreme psychological and physical distress. Packed together so tightly that they can barely move, they suffer from osteoporosis and resulting bone fractures, and are often subjected to painful beak trimming and starved to speed egg production.

Egg Labels – Free-Run, Cage-Free, Free-Range, and Organic

Obtaining nutritionally superior free-range eggs is not as easy as it appears. Some free-run or cage-free hens live out their lives in darkened sheds, not caged, but still denied access to outdoor pasture.

Free-range hens are supposed to have access to outdoor pasture, but because free-range claims are not verified by third parties, there is the possibility of fraudulent labelling. “Farm Fresh” and “All Natural” labels are also misleading, as they provide no information about the treatment of farm animals or the diet they are fed. Only organic and certain humane certification labels requiring outdoor access are verified by third parties. Unless you plan to purchase only eggs with humane certification, learning about and purchasing from local farms is recommended to ensure that animal health and welfare standards are high.


    • Canadian Coalition for Farm Animals. (n.d.). “The Truth About Battery Cages and “Facts About Our Food – Battery Hens”; (October 2005). “Battery Cages and the Welfare of Hens in Canada: A Summary of the Scientific Literature.”
    • Lawrence, S. (Reviewed by Chang, L., MD. 10 March 2006). “Eggs: Dietary Friend or Foe.” WebMD,
    • Long, C., & Alterman, T. (2007). “Meet the Real Free-Range Eggs.” Mother Earth News,
    • Schmidt, S. (2009). “Cracking Egg Labels: Confused by Terms Like Cage Free and All-Natural on Egg Cartons? Our Guide Will Help You Be a Savvy Shopper.” Natural Health, October 2009,
    • The Humane Society of the United States. (n.d.). “Synopsis of Expert Opinions on Battery Cages and Hen Welfare.”
    • Vancouver Humane Society. (n.d.). “Misleading Egg Labels.”
    • Wageningen University, The Netherlands. (2009). “Biological Value.”

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