Quick question- I was having the same issue with a particularly aggressive roo, and initially I tried the "separation" technique, where I let the girls and the other roo out, but kept the aggressive rooster in the run. The first 5 minutes were terrible! He was squawking and growling, and then he began flinging himself against the hardware cloth, but eventually (30 minutes) he calmed down, and when I let him out he SEEMED a bit less aggressive.
The other day though he was aggressive towards me, so I picked him up, held him, but when I put him down, he ran over and began pecking all of the hens and the other rooster!
Has anyone ever had this happen?
I might just go back to the separation method, definitely don't want a repeat of that behavior!