Which of the following factors usually affects the colour of egg yolk?
Answer Details
The factor that usually affects the colour of egg yolk is the type of feed given to the laying hen. The colour of the yolk is determined by the pigments, primarily xanthophylls, that the hen ingests and deposits into the yolk as it is formed. Hens that are fed with diets rich in xanthophylls, such as corn or alfalfa, tend to produce yolks with a darker, more orange-yellow colour. On the other hand, hens that are fed with diets low in xanthophylls, such as wheat or barley, tend to produce yolks with a lighter, more yellowish colour. Other factors, such as age of the hen or type of housing, may indirectly affect the colour of the yolk by influencing the type of feed given to the hen, but they do not directly affect the colour of the yolk. The colour of the cock, however, has no effect on the colour of the yolk.