The colour of the yolk is influenced by substances called carotenoids. The nutritional value and the taste of the egg is not affected by the yolk colour, although a deeper yellow/orange might seem to do just that! The intensity of yolk colour may be measured against standards, like the Roche Scale (Pictured above), and eggs produced by hens fed on a diet of the normally used natural grains/pulses as used in SA would invariably result in a scale measurement of 6-8. The most important sources of carotenoids in poultry feed are yellow maize (corn), maize gluten, alfalfa (lucerne) and grass meals. In South Africa, Yellow maize is the primary energy source for all types of chicken feed and it is rarely required to add pigments. When yellow maize is replaced with, for instance, white maize as an energy source in the feed, it is necessary to add some natural colorants like caretinoids obtained from marigold petals/ carrots etc, to ensure that an acceptable yolk colour is achieved. Misuse of colorants leads to “orange” yolks and this effect is sometimes abused to create a “Natural/Free Range/Organic” feeling. This does not mean that all orange coloured yolks are manipulated, but an “orangy” yolk is no guarantee that the eggs were produced in a more natural/organic way than other eggs.
