Rooster is henpecked

[BlindLemonChicken]

Another idea is if it is just one instigator, to isolate that one for a bit instead of the rooster. This may rearrange the pecking order and stop the behavior

I would try this. Every time you try to reintegrate him he has to start over at the bottom of the pecking order. Find the dominant hen and remove her for a while and see if that helps.