What are your goals with chickens? How do males fit in with those goals? The only reason you need a rooster is for fertile eggs. Everything else is just personal preference. Personal preference can be strong, some people would not have a flock without a rooster even if they don't want fertile eggs. Others do not want a rooster anywhere near their hens. It doesn't matter what my preferences are, what are yours? I generally suggest you keep as few males as you can and still meet your goals. That's not because you are guaranteed problems with more roosters, just that problems are more likely. For a lot of people, the correct number is zero.
Those are my standard comments to people in your situation trying to make up their mind. I see you got rid of one. I consider that a great decision but you may still have one or two more decisions to make. At four months you don't have a clue how they will act as they go through puberty and later as roosters when they finally mature. There can be a world of difference in how cockerels behave and how mature roosters behave. Pullets go through maturity also but usually not as violently. I've had cockerels start puberty at 3 months, others not start until after 5 months. I've had some 5 month old's act like a mature rooster, I've had some not make that change until they are about a year old. People like to give hard and fast numbers as to what age these changes take place but in my experience real life does not work that way. My numbers are skewed too as I raise mine to eat and most of the slower maturing ones don't live that long.
You still have one or two to go. Watching cockerels and pullets go through puberty can go pretty smoothly, especially when they have a lot of extra room. But usually, even with room, it can be hard for the faint-of-heart to watch. It can get pretty violent. If you decide to try to keep a cockerel, I suggest you have a pen ready where you can isolate one pretty quickly if you need to. (Having a place like that ready anyway is a good idea in case you need to isolate an injured chicken.) I also advocate making these decisions based of the good of the flock as a whole as opposed to one individual flock member.
If you decide to get rid of one I think the sooner the better. That way you are doing it on your terms, not due to an emergency. When you let one go you no longer are in control but you sound like you might put some effort into that. I also think your remaining flock goes through less disruption when they are younger. They are probably in flux anyway determining dominance and pecking order.
Good luck however you decide. There are people that keep them, some that don't. To me neither one is the wrong decision, just the one you chose.
