My roosters that I have had that are Rhode Island red and barred Plymouth rock have always been the most aggressive, but there may be breed exceptions.
In my experience withroosters (we have had around thirty in the past four years) a breed called "silkie" chickens, the roosters of that breed are sometimes even nicer than the hens! I have been...
Some breeds that have been known to be more aggressive than others include: American Staffordshire Terrier (aka PIt Bull), German Shepherd, Akita, Chow Chow, Doberman Pinscher,...