I would segregate the bullies into classes run by former Marines--not joking. These guys are tough and won't stand any nonsense from jerks. By separating the bullies from the main student body, you protect those who are weaker, or just different from them. You also reduce the amount of trouble caused by regular kids who might other wise join in with some of the bullying. The separation also needs to be during lunch, gym classes, study hall, library time, music, etc. The bullies must be kept apart from the other students during all activities to prevent them from doing it. Unfortunately, that won't happen because the parents of these "cream puffs" would have a fit, and sic a lawyer on the school. That leaves suspending or expelling the worst offenders, and for the rest of the time, the weak and different kids have to take their chances or themselves be segregated into special needs classes. Some do need special classes for learning and behavior help, but the bullies still get access to them. The schools don't do enough to protect kids from bullies.
If I had kids I would home school them, instead of throwing them into the school meat grinder.
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If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau