When I ordered my BR chicks I chose them because of their strong personalities. I knew they needed to be at least somewhat assertive in order to deal with my RIR's. Yesterday during the dinner break one of the BR's flew into the run. Only one hen chased her but no murderous type pecking occurred. A second one tried the same thing and ended up running through the entire run. A little chasing, but then right back to their safe place. So I think taking it slow is working. I keep hoping.