I used to pen each of my little flock separately - the sheep all used the same pen each time without being trained and the ram slept in the corridor once the pen gates were shut. In the day they all went out together, though I usually kept in the mums with new borns for a day or so, and a bit longer if the weather was foul. By penning them individually it made it easy to see who was eating well and also the ram or bossy ewes didnt get more their fair share of the good stuff