Contrary to popular belief good hen eggs do not normally have a rich, orange-yellow yolk. The colour depends on the bird's diet and it's not common for free range hens to eat a lot of yellow pigmented food. The much-touted rich yellow colour that comes in eggs from factories, where the hens never see the light of day, is a result of large amounts of food colouring being added to their feed. The typical yolk of the free range egg will be light yellow.