What's your definition of a "pen"? I've been on a fenced property that covered 50,000 hectares, and when some people heard that it was fenced, would have nothing to do with it. I feel that for most plains game, any property over 3 or 4 thousand hectares, with sufficient cover and uneven terrain which allows an animal to make good its escape is "huntable" by my standards. On the other hand, I've seen properties of 5 to 10 thousand hectares that had virtually no cover at all. That is one of my definitions of a "pen", and I wouldn't hunt on it, because the animal has no chance of escape unless it could run all day.