I've had the same experience--they look like they're separate flocks, but there's always poaching.
When you're getting ready to hatch, just pull the little guy out of the flock for a few weeks. A good 2 weeks to clear out any sperm a hen may have stored from him, then however long it takes you to collect eggs. Then he can come back with the flock.
When you're getting ready to hatch, just pull the little guy out of the flock for a few weeks. A good 2 weeks to clear out any sperm a hen may have stored from him, then however long it takes you to collect eggs. Then he can come back with the flock.

