Exploring How Feed Affects Egg Yolk Color
What Influences Egg Yolk Color and Nutrition?
By Doug Ottinger – Many chicken owners know that egg yolk color is heavily influenced by the feed their birds eat. But do they really understand how interior egg quality can be impacted by the feeds the chickens eat? For instance, most know chickens fed lots of green feed will produce deeper yellow or orange yolks. But why? It’s because of high levels of beta-carotene in the green feed. The beta-carotene is processed in the hen’s intestines into a substance called retinol and then absorbed as vitamin A.
Is there a link between egg yolk color and nutrition? Color alone is not indicative of an egg’s nutritional value, but there are substantiated correlations between hens’ diets and the nutritional content of the eggs produced. Eggs with deeper yellow yolks usually have higher levels of vitamin A. Some studies have also indicated there may be higher levels of other micronutrients. Past studies indicate that pasture-raised chickens, which consume much green feed and produce deeper-colored yolks, may produce eggs that have lower levels of cholesterol and contain higher levels of Omega-3 fatty acids.
Today, many people view the deeper color, higher vitamin A content, and potentially higher micro-nutrient levels from eggs laid by chickens in a more natural, open-pasture setting as a better choice for their families.
We live in a time of readily available, commercially-processed, perfectly-balanced feeds. Consequently, most of us rarely need to think about what to feed chickens for maximum production or health. We are even further removed from realizing how certain feeds can sometimes impact the interior quality of the eggs.
It was only 60 to 70 years ago that many poultry keepers formulated their own feeds or fed their birds a mixture of available grain or local gleanings. This was a time when those who kept poultry were often aware of how diet could affect egg quality.
Most people today do not mix and formulate their own feed, but there are a few self-sufficient homesteaders who still do this. Whether you are like most and buy the prepared feeds or you are among that self-sufficient group that sources-out and mixes homemade poultry feed, what your hens eat can significantly impact the internal composition and look of the eggs. Here are a few lesser-known egg facts about how feedstuffs can affect the interior quality of an egg.
Green Feed and Egg White Quality
We normally think of green feeds as producing high-quality eggs. However, hens fed excessive amounts of green feed can produce eggs that contain much higher levels of thin egg white or albumen. Eggs with thin or runny whites normally are thought of as lower quality or being old. Not something to worry about too much, but if you see this happening (especially if you sell the eggs), cut back on the green feed and it should help.
Green Feed, Carotenes, and Egg Yolk Color
Green feeds contain beta-carotene which makes yolks deep yellow or orange. Some feed manufacturers use natural substances like marigold extract to get the same results.
Cottonseed Meal and Discolored Yolks
Whole cottonseed and ground meal are a nutritious feed source used in many animal feeds, including dairy rations. The protein content of cottonseed is high; about 41 percent. Feed manufacturers, however, learned many years ago to keep it out of laying-hen rations or use it very sparingly. A compound in the seed, known as gossypol, causes the egg yolks to turn a pinkish-red or olive-color after three to four weeks in refrigerated storage. Chickens consuming large amounts of cheeseweed, a common weed related to cotton, can also cause the same problem. While the eggs are reportedly wholesome and still good to eat, very few consumers have an ability to stomach olive-colored egg yolks.
Fish meal is a nutritious source of protein and micronutrients. Use too much, however, and the eggs taste like fish. This is another item that feed manufacturers learned to use sparingly in laying hen diets.
Rarely used today except by those who formulate their own feeds from naturally-gleaned components, acorns contain high levels of protein. Ground acorns were used in some regions many years ago as an ingredient in poultry feeds. Used in levels up to 20 percent of the total ration, the dormant, ground acorns caused no problems, but if the whole acorns got wet and sprouted, hens that ate large amounts of them produced olive-colored or brownish yolks. Farmers learned to keep laying hens away from sprouted acorns.
White Corn and Light Colored Millets
Yellow corn is used in most of the world in poultry diets and helps contribute to yellow egg yolk color. However, in areas where lighter colored millets are used as a main ingredient in the feeds, egg yolks are often a very pale yellow or almost white.
Pimiento, Dried Red Peppers and Annatto
Research done in the early 20th century showed that hens fed diets high in powdered pimiento or other red peppers, produced eggs with red or brownish-red yolks. The natural pigments in annatto created orange-red to completely red yolks.
Breed Differences and Duck Eggs
Different breeds often process the same pigments in different ways as part of their genetic makeup. Breeds such as Leghorns living in the same pen with breeds like Rhode Island Reds or Marans, and fed the same diet, will often produce lighter colored yolks than the Rhode Island Reds or the Marans.
What about duck eggs versus chicken eggs? Many epicures and cooks have their preferences for one or the other in certain dishes and culinary uses. Duck eggs are normally thought of as having deeper colored yolks, thicker albumen, and thicker shells. The eggs also have a protective waxy coating to protect them from the elements that make up a waterfowl’s natural habitat. The same feed issues that affect the internal composition of chicken eggs also affect duck eggs. Egg yolk color is greatly influenced by the same pigments in the feed. Shell quality of both chicken and duck eggs is highly dependent on making sure they have a proper calcium and phosphorus balance in their diets.
Living in a time of readily-available, balanced feeds, few of us seldom stop and think about what to feed chickens or other fowl. We forget how diet may impact egg quality. Even though we may not think much about it anymore, it is still fun to learn how feeds that poultry eat can affect the interior quality of the eggs.