The problem with the Marans is an ongoing one, people wanted dark eggs, dark eggs went for high dollar, everybody got Marans, bred only for darkest shell color.
Then a proposed "standard" came up and was put before the APA. Shows were held and low and behold the birds didn't match the standard. The color is all over the board etc etc. Another show was scheduled then cancled. Last I saw it's 2011 before another qualifing show is planned, that shows you how far off the birds are.
Now it's all about conformation and watch the shell color suffer. If you want dark egg layers buy them now unless some breeders keep breeding them that way.
Another big problem with the birds is most of the lines of Marans have all been mixed. there are very very few pure lines left. There is only one Cuckoo line left to my knoweldge that is still pure. BC's are in about the same state.
In our experience marans eggs (Cuckoo and BC) are not hard to hatch at all - we have very high hatch rates from ours, I think the problem stems from shipped eggs, inbreeding.
Steve in NC