rooster abusing hens

I have had this bantam cochin rooster (Piccolino) for several years now and he has been wonderful. He has been great to the hens in the past but all of a sudden he is very aggressive. My family moved a few months ago and I built a new coop and run. Our new situation doesn't allow for free ranging like the last place so now my birds are cooped up (in a large coop w/ run). I have two large standard hens which are very old (9 yrs+) two penedesenca pullets, a bantam hen and a bantam pullet and another bantam cochin cockerel in one side of the coop which is large (8X10). Recently Piccolino has become very aggressive, particularly towards the older hens. I have come quite attached to my roo so I don't want to get rid of him, but his abuse is become severe and my older hens (who were my first and second chickens) have been getting injured. I separated the hens for a while but I don't have a good place to put them so I had to return them to the coop. I am unsure what to do. I am selling the younger rooster at the auction this Saturday, and I'm wondering if I should send Piccolino too. Is there anything I could do to stop this abuse?