Where's the Copper? This looks like a Black Marans. Nothing wrong with that, smile. Needs more depth of breast. And looks a bit pinched in the tail. Maybe it is just the picture. I have seen a lot worse. This is a hen?
I would breed it to a large full breasted mate with a wide body and long flat back. Take a look at the Little Peddler Marans website. That/s the silhouette you are seeking.
Best,
Karen