I think if you started focusing on that with the birds you have at home you should do well to have a nice bird for processing. The flavor on the Marans really can't be beatProbably both as I expect the number of roosters to out number the number of hens. If I want to breed and hatch chicks, well . . . you get the picture. Need a destination for most of the birds.
As marans are dual purpose, I wondered how much emphasis is put on muscle development for eating purposes.