Why are different egg yolks different colours?

Different egg yolk colours

Ever crack open an egg and notice that the yolk is a lighter or darker colour than usual? That’s because not all egg yolks look the same, and it’s entirely possible (and normal) to see different shades of yolks from one batch to another.

Why is this? It’s all in the feed. The diet of each hen will affect the colour of the yolks. Diets high in green plants produce darker yellow-orange yolks; diets high in corn-based feeds produce a darker yellow yolk; and diets high in wheat-based feeds produce a paler yellow egg yolk.

According to the website (which is produced by the Egg Farmers of Canada), yolk colour does not affect the flavour, nutritional value or quality of the egg.