Marans: Differentiating FBC, Wheaton & Partridge cockerels

[mdenham]

In adult males, it is possible to distinguish French Black Copper (FBC) Marans from Wheaton Marans by the orange wing-bow/triangle. However, for young cockerels of 6-8 weeks old, I have a mix of 3 different colours. Since they do not have the wing bow developed I am assuming that it is impossible to tell FBC from the Wheatons from tge Partridge cocks at such a young age ... in fact I don't even know what the difference is between the adult male Partridge and the adult males of other two (FBC & Wheaton). The reason I have this problem is that I purchased 150 "FBC" eggs from a breeder and realised that they had, in fact included 5 or 6 different colours/varieties of the breed - not pleasant! I would be greatful for any help.