Sounds like you're doing all you can do.
Again X2 on what Yakima Kid said, it's always the family line not the breed, no matter what trait you're talking about; some traits just crop up more often among family lines raised under certain environmental situations, i.e. neurotic and aggressive behavior being far more common among intensively caged and socially disordered/isolated birds.
People often tend to overgeneralize i.e. 'all Buff Orps are good mothers' or 'all Leghorns are too noisy' (I've probably said the last one myself, or something close to it)... But again it's just family line. Some of those rates of occurrence can be very high though, so high you can end up giving up on the breed sometimes.
Best wishes.
Yeah. I gave up on white Leghorns for just that reason. No matter how I housed them or fed them or whatever, their were always nasty, cannibalistic chicks in every batch.
I need to start segregating one of my Dominiques. She pulls feathers on chickens, and pants on people. I'm worried that she might take up vent picking.