I helped out with a couple European style pheasant hunts at a hunting preserve and was fascinated with the process. The birds are not raised at the preserve, but they are housed there. One technique used to keep them from fighting so much is to turn the lights off. Birds rarely escape the pen, but not all of them are shot during the hunts (some of the ones I have seen are pretty bad--less than 50%). Some of these birds will try to get back to the pen and get trapped in a cage nearby. Unfortunately, there is a critter eating the trapped pheasants. It was assumed to be a raccoon, so I recommended getting dog proof traps, but it turns out it was a Marten, which has not been caught since the last time I was over there.