What you have matures much faster than mine. Mine do not look like that until pushing 20 weeks. They look like games. Ideally you let them run as a group as long as you can to allow good physical development. With experience you can tell when they need to be penned. Since just starting, I assume you are a novice. Set up two pens now that are at least 4' x 4' and ideally just as tall. Pen the two separately so they can not reach each other or other roosters through the pen walls. You will fairly quickly see a change in behavior.