We had one like that and all we could do was keep it separated and eventually found it a new home. Same thing another time all of the hens picked on one victim. Just rehomed the victim. Sometimes things just don't work out with chickens.
At least someone is trying to help rather than trying to be “funny”.
Unfortunately some chickens are just arseholes. Sometimes getting another chicken can help (changing the dynamic of the flock) but usually it’s simpler to re-home the nasty chook.
Edit to make sure OP has done the basics like ensuring the flock has enough space, enough room at night to roost, enough food etc?