we have a horse farm in a rural area and i am planning to add chickens. several barn cats presently reside in the horse barn. do i need to confine the chickens to a fenced-in run or can i let them roam freely around the barn and farm? how far will they wander from the coop if not fenced in - there is a road approximately 100 yards from the barn. if fenced run is recommended, how tall does the fence need to be?