The approach to pasture allows to hens feed with their natural diet. Because they are omnivores, on a pasture, they can eat grass, worms and various insects. Hens are not vegetarians. If they fed only with grains, it is unnatural for them, and their eggs (or meat) will not offer us any nutritional quality.
For some, pale yolk means cage breeding, for others the orange color of egg yolk reflects the artificial dyes intentionally added to the hens’ diet. In fact, all the eggs (in the picture below) come from free-range laying hens (which according to European legislation means that the hens must have unrestricted access to the range throughout whole day, which must be covered mainly by vegetation), and no eggs in the picture come from hens fed by diet with artificial dyes. These eggs were provided by Mother Nature.
You should know that hens with access to pasture obtain natural pigments, called carotenoids, from grass. Their significant sources are also nettles, alfalfa and marigold, or corn, which can be part of hens feed, or peels from colorful vegetables or fruit (such as beets, zucchini, watermelon or carrot) if the owner provides them with leftover food:-). However, carotenoids are not only pigments, they are distinguished by their antioxidant properties. Their intake from food is associated with a reduced risk of cancer, cardiovascular disease, age-related macular degeneration and cataracts.
In addition to the higher proportion of carotenoids, a recent study by Popova et al. (2020) found that egg yolks from free-range hens have 40% higher amounts of vitamin A and almost twice as much vit E compared to eggs from hens without access to pasture. Also, the ratio of omega-6 to omega-3 fatty acids was lower in free range eggs, 15.35 versus 24.21. The recommended value of this ratio is 4.
Popova T., Petkov E., Ayasan T., Ignatova M. (2020): Quality of Eggs from Layers Reared under Alternative and Conventional System. Braz. J. Poult. Sci.: 22(1).
Nařízení komise (ES) č. 589/2008 ze dne 23. června 2008, kterým se stanoví prováděcí pravidla k nařízení Rady (ES) č. 1234/2007, pokud jde o obchodní normy pro vejce. Dostupné z: https://eur-lex.europa.eu/legal-content/CS/TXT/?uri=celex:32008R0589