Nutritional Value Is the Same for Free Range or Cage Eggs

— Written By James Parsons and last updated by

The general public often thinks that eggs produced by free-range hens are nutritionally superior to eggs obtained from layers kept in traditional battery cages. However, a recent scientific study has called this popular perception into question by finding essentially no differences in the nutritional quality of eggs produced by hens from both management systems.

Dr. Ken Anderson, a professor in the Department of Poultry Science at NC State University, recently conducted a scientific study titled “Comparison of Fatty Acid, Cholesterol, and Vitamin A and E Composition in Eggs from Hens Housed in Conventional Cage and Range Production Facilities.”  Dr. Anderson collected data for the study in 2008 and 2009. The study was conducted with the North Carolina Layer Performance and Management Test (NCLP&MT), which evaluate the major commercial layer lines used in the United States.

Dr. Anderson conducted his study in North Carolina using more than 400 Hy-Line Brown pullets. The pullets were raised in accordance with the laying environment (range or cage) in the 37th NCLP&MT. All of the pullets in the study were hatch mates. Identical rearing dietary program were used for both the range and cage pullets, with the only difference being that the ranged pullets had access to range paddocks that had a common hay mixture for North Carolina comprising both warm and cool season forages.

Pullets designated for the range facilities were brooded on litter until 12 weeks of age and them moved to a range environment. At 17 weeks, they were moved to one of three production range paddocks. A parallel pattern was followed for the cage hens, which were reared in a cage rearing facility. At 17 weeks, they were assigned to one of the three groups of laying cages. All other rearing parameters were maintained as similar as possible.

Egg samples were collected at 50, 62, and 74 weeks of age during the productive life of the flocks and sent to four different laboratories commonly used for egg nutrient analysis. The results showed no influence of housing environment (range or cage) on egg levels of vitamin A or vitamin E. However, beta-carotene levels were higher in the range eggs, which, according to Dr. Anderson, may have contributed to the darker colored yolks observe in those eggs during the study. The study also found no difference in cholesterol content between range and cage produced eggs.

Based on these results, Dr. Anderson concluded, “a significant nutritional advantage of eggs produced by chickens housed on range versus cages could not be established.”  He said, “The key takeaway from this research is that an egg, no matter where it’s produced is a very nutritious product. Eggs from a range production did have higher levels of total fat than eggs produced by caged hens, but they did not have higher levels of cholesterol. Perhaps the most striking finding was that both cage and range produced eggs actually have lower cholesterol levels than previously believed, which has led the United States Department of Agriculture (USDA) to lower the cholesterol guidelines for eggs in the USDA Nutrient Database for shell eggs to 185 mg per egg, down from 213 mg.”

If you have any questions or comments, please feel free to contact me, James Parsons, Area Specialized Poultry Extension Agent, at North Carolina Cooperative Extension, Hoke County Center, at 910-671-3276 or by E-mail at

North Carolina State University and North Carolina A& T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, or disability. In addition, the two Universities welcome all persons without regard to sexual orientation. North Carolina State University, North Carolina A&T State University, U. S. Department of Agriculture, and local governments cooperating.