my cocker is nearly blind due to faaarked up breeding (dont get me started) even on his good day a dead duck on water is fairly safe if more than 50 yards away....chuck a rock in its direction to give him a clue and his nose will take him the rest of the way.Ive seen heading dogs spot pigs at 6-700 mtrs but they had clues by us humans watching them,and come to think of it you can give arm signals from a long way away too.
Bookmarks