Why do eggs have different colours?

Each week, we ask you to share your questions about farming, food or Sacrewell with us on Facebook. The person who writes the best question wins a free tractor ride for a child and accompanying adult, as well as having their question answered on our website. This question came from Monika Budakiewicz:

Our egg collection at Sacrewell shows that eggs come in a wide variety sizes and colours. This can be because of the size of the bird, their nesting behaviour and the environment that they naturally live in.

You might expect, therefore, that all farmed chickens would lay a similar colour of egg, but this is not the case. Different breeds of chicken lay distinctly different colours of egg, and even within an individual breed there can be variation in the shade.

Some examples are:

Chicken Breed Egg Colour
Araucana Green/blue
Ancona White/cream
Barnevelder Brown
Frizzle White/tinted
Lincolnshire Buff Tinted
New Hampshire Red Brown
Orpington White/tinted

Hybrid chickens are not pure bred and so it can be difficult to predict which colour their eggs might be. One clue can be found by looking inside an individual hen’s ears. Hens with pale ears lay pale eggs, whilst hens with dark ears lay darker eggs. The colour of a hen’s feathers does not relate to the colour of their eggs.

Changes in diet and stress levels can cause one chicken to produce eggs which are different shades on different days, but this would only be a small change in shade rather than a pronounced switch between different colours.