Its good that you have removed him from the flock.Yes, we will give an ultimatum. He cannot get into our run it has a roof or the coop they are fenced in, roofed, etc and so he needs to find somewhere else to be. We are going to wait a couple of weeks then he will have to be rehomed. He has his spurs so. I am very careful of him as are our dogs. We are angry that the other rooster and hens cant live in peace, so we will work hard to find a solution that's great for everyone.
I always like to give them a chance, sometimes more, but my first priority is a stress free flock. If you rehome him, please give the new owner a full disclosure. Also, if he is running free, be sure he cannot harm visitors or delivery people.