I have one thing to comment on....when you use an EE to try to make OEs, you don't know the genetics of the rooster. He could be carrying a recessive white egg shell gene which means you won't get those olive greens. To make sure you get olives, you should choose a rooster who has the double copies of the blue shell genes. Those would be true Ameraucanas or Legbars. No matter what you breed these types of roosters with, you would get blue or green egg layers. The darker brown the hen lays, the darker greens you would get....so, yes, a Marans or Barndevelder or some Wellsummers for the hens would give you nice olive eggs. The Wellsummers would make some nice speckled olive eggs.
And, just FYI, there are only two egg SHELL colors....white and blue. All brown eggs are just a different amount of brown coating over a white shell. The brown coloring in the bloom is a by-product of the blood system. (Dried blood is brown) Depending on the breed of chicken, the amount of brown coating (by product) on the egg gives you your different shades of brown. All green eggs are that same brown coating (by product) over blue shelled eggs.
When thinking of colored egg genetics, you must first think of what colored egg shell your chicken has. Then, you go to the amount of brown coating your breed of chicken produces.
White and blue eggs have no brown coating (blood by product) in their bloom.
