So far all of my Marans roos have been very sweet. I have had many breeds throughout my life and have found no connection between breed and aggressiveness of the roos. I've had sweet game roos and nasty barred rocks. I would say my Marans roo is one of the sweetest boys I've ever had. The roos I've gotten from him are as well. Could it be genetics I wonder? Are all of your mean Marans roos from the same mean father?
my experience is the same, all of my birchen marans roosters/cockerels have been huge sweethearts, very mellow and easy-going.