Exposing Chickens To Sunlight Can Help Boost Vitamin D Levels In Eggs

Vitamin D is called the “sunshine vitamin” by many people. Vitamin D is a nutrient the body needs to absorb calcium, magnesium and phosphorus. It belongs to a family of cholesterol-derived compounds that come in two main forms: vitamin D2 and vitamin D3. Vitamin D is also known to many as the “sunshine vitamin” because both D2 and D3 are produced by exposure to ultraviolet light.

Vitamin D also plays a role in keeping the immune system functioning properly. Enough vitamins can promote the normal growth and development of bones and teeth, and improve the body’s resistance to disease. But the truth is that many people suffer from vitamin D deficiency.


Vitamin D deficiency is not only associated with brittle bones, but also with an increased risk of respiratory disease. To boost your vitamin D levels, experts recommend adding eggs to your diet, especially those from free-range chickens, whose yolks are rich in vitamin D. Like humans, vitamin D in chickens is produced by exposure to ultraviolet light.

In a recent study published in the journal poultry science, nutrition and agricultural scientists from the university of martine halevetenberg in Germany reported a relatively simple new way to increase vitamin D levels in eggs: exposing chickens to ultraviolet light.

A team of researchers led by nutritionist Julia Kuhn conducted the study to find a solution to vitamin D deficiency.
“Many people don’t get enough vitamin D because of their lifestyle, especially in the winter when there is a lack of sunlight,” Kuhn explained. Eating eggs rich in vitamin D could be one way to solve the problem, he believes.
Together with her colleagues, Kuhn set out to find ways to stimulate chickens to produce natural vitamin D. Based on earlier studies, they used ultraviolet light to illuminate the legs of chickens. Kuhn points out that these studies are ideally conducted under controlled conditions. They chose to experiment on a chicken farm to test the practical feasibility of the method.

The researchers used two breeds of chickens and kept 24 of each breed indoors before the experiment. Over the course of the study, the researchers also analyzed different factors that could influence vitamin D levels in the eggs the chickens produced, including the type of chicken, the type of lamp and the amount of light the chickens received each day. The researchers also looked at the effects of these ultraviolet rays on chickens’ behavior and egg production.

“Humans can’t see ultraviolet light, but chickens can. So light is a key measure for the chicken industry because it affects how chickens lay their eggs, “said Eberhard von Borell, a livestock expert and one of the study’s authors. The researchers videotaped the chickens during the experiment, used the videos to assess their behavior, and examined their feathers to assess their mobility and aggression.


After six hours of daily uv exposure for three weeks, vitamin D levels in eggs increased three to four times, depending on the breed of chicken, the team reported. But the levels did not increase over the next few weeks.

The researchers also said the ultraviolet light did not have any negative effect on the chickens, because none of the chickens actively avoided the light or behaved differently. This shows that their method is feasible.

Although researchers have been able to increase vitamin D levels in eggs using ultraviolet light, there is a better solution: sunlight. Simply put, free-range chickens can increase the production of vitamin D in their eggs, and a more professional option is to build a solarium for chickens, which allows them to get plenty of sunlight in a safe and controlled environment.