They have not yet been admitted to the APA, but most likely will be by next year. It's not so much that they are "rare," they are sought after due to the darkness of their eggs. If you really get out there and do your research, you'll find that lots of folks are selling hatching eggs that are not nearly as dark as they can or should be.
You'll find some breeders that do an excellent job with conformation as well as egg color - one of which is Bev Davis. Here are some hatching eggs that I purchased from her:
Edited to say: I didn't mean to make it sound as if anyone selling eggs lighter than these is not a serious breeder; there are many things to take into consideration when breeding, and there are many folks working on faults and making huge progress in the breed, and also working on egg color.
they lay the coveted *chocolate* egg. Most think it's just a fad right now, therefore the high prices. They have a wonderful temperment also. If you are patient and research well you can get some at reasonable prices, but there is always a waiting list.
True Black Copper Maran are rare. They are usually in high demand as well because they are supposed to be the darkest layers of the Maran breed. Be very careful who you purchase eggs from because there is a lot of potential out there to be taken advantage of.
I do know of some breeder with Cuckoo Marans that lay an 8 on the scale. But for some reason, folks tend to seem to like the copper blacks better. I'm unsure why; I think the Cuckoos are really pretty!
I think it's because of their coloring. All black, with touches of red. Cuckoos are too often confused with barred rocks or dominiques by those who don't know better. And the mindset that they're the darkest layers of all because they're closer to the french line, blah, blah, blah, etc., etc., etc...
I have two cuckoo pullets and two black copper pullets. They've not yet started laying but they're close!
I hatched them from eggs bought from Mergmet (Margaret).
Ummmm.....not so good. I was pretty disappointed (I didn't hatch them myself, I have a friend who is very experienced in hatching and she hatched them for me). Out of 14, 1 had a hole in it when it arrived. Of the 13 left, only 3 hatched. I think they must have been handled roughly through the US mail, because we also hatched some Ameraucana eggs right along with these, and the Ameraucanas all hatched without issue. I'm extremely pleased with my cockerel, Francoise - here he is at 16 weeks:
WOW! I really need to Shop-Vac the cobs in my barn!