Do Bantams get along with full size chickens?

[OrpingtonAustin]

I've had several full size chickens for quite awhile now. Buff Orpingtons and Plymouth Rocks. I was thinking about getting some Bantams! I was wondering if they would get along with the big ones and not get picked on? Another thing: What kind of roosters do you suggest. I want a somewhat nice breed, but one that will protect a free ranging flock.