Definitely read through that thread. It is good info and some good knowledgeable people are contributing.
Whether the Marans is the hen or rooster doesn’t matter. What matters is the genetics the Marans brings to the table. Not all Marans hens lay real dark eggs. Not all Marans have the genetics for really dark eggs. So whether it is male or female, it really helps to know that it comes from a flock that lays really dark eggs. With a hen you can see what color of egg she lays, but with a rooster you need to know what color egg he hatched form and the color of egg his grandmothers laid to get a good idea.
It gets more complicated. Some Ameraucanas have a gene that restricts brown. Not all do but some do. If you are unlucky enough to get one of these, even if the Marans contributes real dark brown, the Ameraucana might wipe it out or at least some of it.
Still, your best bet is to get a chicken that lays a really dark brown egg and cross it with a chicken that lays a blue or green egg. Which one is male or female doesn’t really matter. You can’t guarantee what the results will be, but the odds are you will be pretty happy. It does usually work, but occasionally there are some unbelievable surprises. I have a hen laying a blue egg now and she should be laying green. Not a dark olive like you want but at least a light olive. I don’t know what happened.
