Olive Eggers: Breeding for Olive Eggs

This is a follow-up post to our previous post Easter Eggers: Understanding Egg Color Genetics

You may need to review that post before reading this one. 

Breeding for a first generation (F1) Olive Egger:

Pure Ameraucana carry two blue egg genes: O/O (this blue egg gene is dominant).
Pure Marans carry two white egg genes: o+/ o+ , as well as dominant brown egg shell alleles & dominant modifiers to make the brown very dark.

The Olive Egger offspring (O/o⁺ ) carry a dominant blue egg gene which means they lay blue eggs, but the dominant brown egg shell allele creates a brown coating over the blue egg shell creating a green egg. Additionally, the dominant brown modifier also makes that same brown coating very dark which creates a darker green, or olive, shade of egg color.

Breeding for a second generation (F2) Olive Egger:

When you breed an F1 OE to an F1 OE, you get various outcomes similar to breeding EE:

IMPORTANT NOTE: This breeding combination gives you the percentages in the above graphic, but there is one important point to note. You must consider the doubled dominant brown egg allele & the dominant brown modifier! This results in all the offspring getting the allele & modifier from both parents, and second generation (F2) OE’s will lay richer olive colored layers. Due to the alleles & modifiers being passed to all offspring, the blue layers should also lay a shade of olive, and the white layers will actually lay a darker brown colored egg. Final results become 75% shades of olive.

• 50 % chance of another olive layer or OE (O/o⁺) laying a richer olive colored egg
• 25% chance of a blue layer (O/O) laying an olive egg more similar to an F1 OE
• 25% chance of a white layer (o⁺/o⁺) laying a brown egg frequently darker than most but not as dark as Marans.

Random personal breeding results to date: We have crossed a F1 OE to a brown egg layer which produced a layer of a nice coppery brown egg. The same F1 OE over a Leghorn produced a very light olive layer (the white genes from the Leghorn essentially lighten the egg color).

Here are a few examples of Olive Eggers we have bred: