Yolk color varies. It is almost completely dependent upon the feed the hen eats. Birds that have access to green plants or have yellow corn or alfalfa in their feed tend to produce dark yolks. Since commercial laying hens are confined, lighter and more uniformly colored yolks are being produced. Yolk color does not affect nutritive value or cooking characteristics.
Egg yolks are a rich source of vitamin A regardless of color.
So there is nothing wrong with greenish whites that are most frequently observed in fresh, high-quality eggs. This condition is noticeable in freshly laid or oil-treated fresh eggs. It is caused by the naturally occurring carbon dioxide. As the egg ages and this gas escapes, the white becomes clearer. The quality and flavor of eggs with cloudy whites is excellent.