One of my favorite gauges, been using that gauge since I was in college in the early 70's....and yes have shot quite a few ducks over decoys with one of my 28's, an older Remington 11-48 auto bored skeet.
Over decoys and within 20 yards....you really have to try hard to miss...lol. Pattern opens up and down they go. Upland bird hunt primarily with a 28, especially years ago over setters....pure death on pheasants and quail....and chukars in the snow when they are down low and holding.
Fast pointing and quick shooting 28's make you a better shot in my opinion. Too many people hunt with too large, too heavy and too tightly choked guns for both upland and waterfowl. Behind dogs and over dekes or even jump shooting, you consistently kill more and when you eat them they will resemble what they originally were and not cube steak...lol.