Good on you for putting the safety of your family before that of a vicious bird. Always commendable.
It's always a shame when people put the quality of life of a bully above that of every other animal and human that bully interacts with, condemning a whole flock and family to ongoing stress...
Does he actually attack them?
Chickens have a chasey game they play, basically practicing their evasive manoeuvres; he might be doing that. Unless of course he's actually attacking them.
If he's only 2 and a half months old, and he's attacking the others, that's not a good sign of what sort...
Hello jemschicks,
Can you explain the situation a little more? It would help to know the answers to these questions: do you have the Polish and Americana separated? Under what circumstances is he charging them? Is their run really narrow?
Best wishes.