Mine free range too, young roosters can and do outrun hens to breed them. I raise and keep quite a few roosters. I find they aren't as crazy when they are initially let out. It can take some time for them to find their confidence again. If he's running straight at hens when released he hasn't been penned long enough from my experiences and I round him back up pretty quickly.You know that when you let him out, he'll probably be more "vigorous" at first, right? He'll have been separated, hormones working, and need that release. Do you really need a rooster? Are you planning on breeding? If not, I would suggest a hens only flock for you. Then you won't have to worry about the wear and tear on your hens from an over active cockerel. I think he'll likely settle down as he gets older, but it's your choice entirely. I have never separated an active cockerel from my flock. I guess it just never occurred to me to do so. But my chickens have always free ranged, so maybe the hens have had a chance to get away from the cockerels as they were going through that hormonal stage.