TY for your input! I like getting feedback from other owners about the behaviors and interactions of their breeds and sometimes I see patterns emerging. I know many breeders say it depends on the breeder's line or that an individual chicken within a breed might be a rogue but IMO there are certain characteristics in certain breeds that seem inherent no matter what kind of line or selective breeding is done. For instance, White Leghorns are notorious for cannibalism or assertive flock behavior so the poultry industry started cross-breeding them in hopes of developing gentler production layers like the California Grays, Austra Whites, Amberlinks, or California Whites.
Our CM was hatched, raised, and handled by a teen breeder who took pride in her flocks. The CM we got from her was never fond of human attention the way her Silkies and White Leghorn from her were. I mean, saying a White Leg was more personable than the CM is saying a lot since Legs are not particularly fond of human handling yet will sit on your arm or lap for treats while the CM would remain aloof. I didn't mind the CM being aloof or standoffish with us but once she started being mean and sneaky cannibalizing our Silkies and attacking them we had enough and re-homed her. She was a large hen, lazy forager, and had a huge feed appetite. Once in a while she layed a #4 solid brown on the egg chart but mostly her eggs looked like speckly or splotchy Welsummer eggs and never the solid chocolate you see in Marans photos. Marans come in beautiful varieties and my personal take is that they should be raised within their own breed or other large dual-purpose breeds to eliminate their temptation to bully smaller or docile breeds in a mixed flock. We've had other large fowl like Ameraucana and Breda that don't take advantage of our Silkie littles the way the CM and eventually the way the White Leg and Buff Legs did.
It's been quite a tap-dancing adventure for us in experimenting with different breeds - White Legs, Babcock Legs, Buff Legs, Cuckoo Marans, RIRs, BRs, Doms, NHRs, Calif Grays, Ameraucana, EEs, Breda, and Silkies. I've also had the pleasure of seeing my friend raise hybrids, sexlinks, EEs, Ameraucana, BCMs, Orps, OEs, Java, and CMs. Our teen breeder source has gone on to college and her mom has whittled down the breeding program to raise only Coronation Sussex now and I was offered a breeding pair from her with the pledge to raise and breed them but I'm not zoned for roos so reluctantly had to pass on that great free opportunity!!! She provides hatching eggs for classroom science and getting Coronation Sussex out in public is providing awareness of this rare Sussex variety.