That answers that....

[Chancy]

Apparently, I will not be getting eggs from my black copper marans ......

 

[Acre4Me]

Sorry!! Been there!! And, in my experience, the Marans are loud and proud.

 

[50-45-1]

Could be you have a crowing hen?
It happens.

 

[Aunt Angus]

I've had both this same occurrence (a "girl" who started crowing) as well as the reverse (a "boy" who laid an egg). What a surprise!

I hope you can keep it. They're pretty roos.