Watch the temperament of your LF around the Polish, EE and bantam breeds. Sometimes there are no incidents but from my research Hamburgs, Campines (Braekel types), BRs, and Sexlinks can get aggressive in their adult stage so just watch them. I am totally unfamiliar with Dorkings or Naked Necks but since they are very LF maybe keep an eye on them too. Even gentle LF can be tempted to pick on smaller gentler breeds just because of the power that they CAN due to their larger size. This is one of the reasons I didn't accept the gentle Coronation Sussex into my yard - the hens get up to 7-lbs and way too large around my 2-lb Silkies - not an equal pecking order fight IMO. I had a 6-month-old Silkie that would've been clawed to death by a 7-lb Marans if I hadn't caught it just as it started - the Marans was gone the next day! I don't keep breeds that don't play nice with my Silkies or my Ameraucana who are my non-combative non-assertive breeds. If you don't want to wait for an incident to happen then separate the Hamburg, Campine, Sexlinks, BRs from the gentler breeds. As for your Dorkings or Naked Necks I am not at all familiar with them and they may be a non-combative breed but they get large so might do better with the LF. In very large acreages the gentler breeds can find areas to hang out away from the aggressive types but in a backyard situation like ours we are just too small to mix assertive LF with gentler breeds. We refuse to add any LF breed weighing more than 5-lb no matter how gentle they are reported to be. So many chickeneers are unaware that a chicken is not just another chicken and temperaments, size, climates, and diets are not always compatible in a mixed flock. You are now armed with info that is up to you to decide what you wish to do.
3 chicks died and we got 4 more after the big chicks were 1 wk old. The new chicks are an EE, a SLW, a leghorn, and a Maran. The Maran might not have been a good idea. But since the silkies are older so I don't think pipsqueak the cuckoo Maran will be bad girl. Our white silkie is bigger than our blue silkie so is it possible that the white silkie, cottonball, would pick on gabby the blue silkie?