The problem is also though that he's agressive. He's not just an oops roosterIt sure is o.k. to pen your "oops" rooster as long as he has room to flap his wings and stretch his legs a little. A 6 foot by 3 foot outdoor run attached to the kennel would work great. Step in stakes, chicken wire, and wildlife netting all over the pen will keep him safe. I have two "oops" roosters in addition to the one I wanted. One is in my small coop about 7 feet by 3 feet. He's pretty happy as long as his favorite hen is with him. Good luck.