I believe the idea of a 2nd layer of exterior wire to be a good one. It needs to be far enough from the inner wire that when/if the owl impacts it it will not reach the inner wire and cause it to vibrate and the birds to react. Covering the pen so that the owl cannot see the birds is also a good idea. Shade cloth is relatively inexpensive as is plastic sheeting. You may not need to keep the covering on long term; if hte owl learns that there is no success hunting at your place, perhaps he will move on.
Visual deterants could include large numbers of free-hanging CDs and windchimes, whirligigs and windsocks, even long lightweight ribbons. You can try flashing strone lights as well. Could also try the motion activated sprinkler.
Visual deterants could include large numbers of free-hanging CDs and windchimes, whirligigs and windsocks, even long lightweight ribbons. You can try flashing strone lights as well. Could also try the motion activated sprinkler.