Hi,
Close, very close. Better than anything I have seen in 2 years. It looks like you have escaped the dreaded pollution by autosomal red. The white
should be at the base of the cock's tail. That is correct. I am not seeing that darker salmon on the breast which is a great thing. I am really impressed by these Marans. Of course the cock's breed type needs improving but considering the very small pool of GSM, that's to be expected. I think there is something going on with the cock's neck hackle, it seems a bit light, should be more "old gold" colored. but I think that can be fixed with careful selection among his kids. Hatch a huge bunch of chicks from these birds. Any percentage of real GSM could be as small as 6.6 or 12.5% of the chicks hatched. You only need a couple real GSM to advance your project. the rest will be color mutts of some kind and just sell on craigslist as brown egg layers. . Congrats on a good starting place. If you can get another truly pure GSM cock that would be great. But you must be sure he is pure. He should have already sired truly pure GSM females. Just males won't do. Males can lie about their color, the females don't. Here is a photo essay of a cock I once owned. I think he is proper GSM colored.
http://waterfordsussexandmarans.webs.com/apps/photos/photo?photoid=88625307
However as chick it was obvious from the brown helmet on his head he was eb/e+ based. That would be eb ( brown) and e+( Black Breasted Red which is the same as Golden Salmon Marans). Do you have pics of this cock of yours as a chick? Did he have a brown helmet as a chick or that proper sharply defined arrow on his head? This is very important to defining your cock's true color base. Where did you get these birds? Congrats, Karen ( former Director of Archives , Marans of America Club )
Here are properly colored Black Breasted Red Old English Game Bantams of both sexes. . They are show quality. Use these as a guide for male coloring.
http://shekinahcreekgoats.com/black_breasted_red_oeg email the breeder for pics of the breast of both sexes. Explain you are working on BBR in
Marans and need some visual help, please. Send him pics of your birds ( natural stance profiles in top, side, front, and rear in both sexes ) and ask him how close he thinks you are and which genes, if any, prevent your
birds from being pure BBR.