We usually pen ours for only a few hours, but the pen needs to be very small so they can't get a run up. This spreads their smell all over each other. If they've got room to take a swing or a run-up at each other then they've got too much room. But you couldn't leave them like that for long as they need to eat, drink and sleep.
Ours always fight a bit when they first go out after the penning, but they usually get bored after a few minutes, especially if we put some food in their trough.
Maybe everyone does this differently, so you can take your pic of replies.