Chalk, there used to their runs, they were there before I started doing anything about them, making more would not neccesarily gain me any benefit, although I know your point, I've seen them snared on trellis, footstyles, trees jumping up at height to access area's.. The wood is not fenced one side, if they were blocked in, they would simply, come round from a different more open angle... Foul catches are not nice with snares, traps, bad shooting, regardless of location its always going to happen, even with breakaways on open runs, nothings fallible...