What gives eggs their color?

[AmyRey]

I've Googled a bit without much luck.

What substance is in the shell that makes a brown egg or a blue egg or a green egg?

What determines the egg color? I know earlobes and genetics, but can that be altered by diet? Environment? Age?

Will my girls always lay the same color eggs?

 

[saddina]

1...

Summary The blue egg character, common among fowls in parts of Chile, behaves as a simple dominant to non-blue. Combined with the various shades of brown it gives a series of greens and olives. Polychromatism in fowls and pheasants’ eggs follows apparently similar lines.

Egg shell color is caused by pigment deposition during egg formation in the oviduct and can vary according to species and breed, from the more common white or brown to pink or speckled blue-green. In general, chicken breeds with white ear lobes lay white eggs, whereas chickens with red ear lobes lay brown eggs.[15] Although there is no significant link between shell color and nutritional value, there is often a cultural preference for one color over another. For example, in most regions of the United States, chicken eggs are generally white; while in the northeast of that country, and in countries as diverse as Costa Rica, Ireland, and the United Kingdom, they are generally light-brown. In Brazil and Poland, white chicken eggs are generally regarded as industrial, and brown or reddish ones are preferred.




2. Breed determines egg colors, but sometimes eggs will get paler towards the end of a laying cycle.

3. Same color, may be a lighter tint towards end of laying.

 

[goldenluver]

it is the breed only not the diet. the only change maybe in shading.

 

[danielbrown]

There are two things that determine egg shell color.
The egg shell it's self, and a color coating on the outside. Both have their own set of genes.
The egg shells only come in white and blue.
The color coating is shades of brown.

Brown egg= white shell/ brown coating
white egg= white shell only
blue egg= blue shell only
green/olive egg= blue shell/ brown coating

 

[Windy Ridge]

Here is the answer.

http://www.mypetchicken.com/How-do-blue-eggs-become-blue-instead-of-H45.aspx?