There's a site called coondawgs.com. They have a large brood pen on it that is 8-feet by 16-feet. I wouldn't keep a dog in there permanently without daily exercise. I understand the parasite avoidance issue but I would also think about the overall wellbeing of my dogs. If you have only a few that you could give daily exercise to, this might be feasible. If you have more than a few, chains is the way to go. JMHO