How olive eggs get their color

An olive egg is a blue egg wearing a brown coat. The blue pigment runs all the way through the shell. The brown is laid down on the outside at the end. Put a fairly heavy brown coat over blue and you get olive, a deeper and earthier shade than the minty green of a light coating. Crack an olive egg and the inside of the shell is blue, which proves it.

How Olive Eggers are made

An Olive Egger is not a standard breed. It is a cross, usually between a blue egg layer and a dark brown egg layer. A common pairing is a Marans or Welsummer with an Ameraucana, Cream Legbar or other blue layer. The blue egg gene is dominant, so if the blue parent carries two copies, every daughter lays a blue-based egg, and the brown parent adds the coating. When the blue parent carries only one copy, some daughters lay brown instead.

Breeds and crosses that lay olive eggs

• First generation crosses of a dark brown layer such as the Marans with a blue layer such as the Ameraucana.
• Some Easter Eggers, which can carry both blue and brown egg genes.
• Back crosses, where an Olive Egger is bred back to a dark brown layer to push the egg darker.

Why olive is so variable

Shade depends on how much blue and how much brown a hen inherited. A cross with a very dark Marans parent tends to give darker olive than one with a lighter brown parent. Sisters can lay noticeably different shades. Over a busy laying season, the brown coat often thins, so olive eggs can drift toward green. After the molt, they often deepen again.

Olive egg myths

• Olive Eggers breed true. They do not. Hatching eggs from two Olive Eggers gives mixed results, including blue, green, olive and brown layers.
• Olive eggs taste different. Shell color has no effect on the inside.
• You can tell an Olive Egger by its feathers. Their look depends on the parents and can vary a lot.

Common questions about olive eggs

What is the best cross for dark olive eggs?

Many keepers use a dark egg Marans paired with a blue layer that carries two copies of the blue gene. The darker the brown parent, the darker the olive tends to be.

Can a rooster's breed affect egg color?

Yes. Both parents pass on egg color genes, even though roosters do not lay. A rooster from a dark egg line can darken his daughters' eggs.

Why is my olive egg turning green?

The brown coating usually fades over the laying season. The blue underneath stays, so the egg looks greener.