By 4 weeks old the males can start causing trouble as they mature faster than the females. But as long as you have a way of separating the trouble makers, even adding a divider in your brooder, you'll be fine. I've always found individuals raised together remember each other so you can remove boys and add them to the trouble makers cage with no problems. Choose your calmest males to breed from. Calm males make for calm females. Good luck - you'll be amazed how fast they grow.
