What breed is this broody???

[ChickenHooked]

So after checking some flock pictures taken pre-black coppers, I've determined my broody definitely is my bcm. She was purchased from a hatchery as a bcm. I'm a little annoyed that I may have been sold a mix instead of a pure bred. Does this happen often? I have an order due in this may from the same hatchery with another bcm in it. How can hatcheries get away with selling mixed breeds as pure breds? The other bcm (that died last month in the nest box) I had from that same hatchery order had no comb whatsoever and was also pure black. Thoughts?