Sometimes we get to the negatives!
I'm in Massachusetts, and the bantams do fine.
I have Silkies, sebrights, old english, d'uccles, and more.
They all do fine in the cold weather.
In the end, it's up to you.
I am aware that they are much smaller and won't get big.
I was just saying, from my experience, I did fine with having bantams and standards together.
As long as you have enough space to where a bantam could run away and hide, they you should be fine.
I actually have a silver duckwing old...
Bantams are usually fine with normal sized chickens.
I have a flock of tiny bantams and oversized large fowl.
They do fine.
The bantams can and will get pecked on or bullied, but it's just part of the pecking order.
If you're really worried about predators, then stick to standard sized chickens.