Depends on the tup. I've known tups penned together so tightly they couldn't turn around and they still managed to do serious damage to each other. Tups tend to get more aggressive as they age. Might be OK if you keep them out of sight, smell and sound of the ewes for most of the year but, particularly with a horned breed, you could get all kinds of, literally, bloody trouble. Don't forget a ram's skull is six times as thick as a human skull and they can sprint at 30 mph for short distances.