Totally up to you. I'd keep the calmest one, or the one you like the most. Their personality isn't certain until after 1 year old, and even then sometimes they change over time.Ok well I only have 4 adult hens, so if I keep a rooster which one would you keep?
Keep an eye on them. Expect your adult ladies to thump them for being presumptuous. Keep the one who learns those lessons and the adults hang out with in peace (the boys will be pushing a year). Also expect hormonal idiocy to start around 6 months. It typically lasts until the first adult moult at about 18 months.