You only need one shotgun if you have the right one, my Remington 1100 auto waterfowler 3" ported magnum will kill anything I ever went after with it. We used to shoot 100 boxes of 25 shotshells each season for geese, another 10-12 boxes of 25`s for black ducks. Another 3-4 boxes for partridge each year. We hunted over salt water for the geese and ducks with 50-70 magnum goose floaters and 30-40 silhouettes for each setup. Took 2 16' deep hulled Princecraft boats to carry it all. The colder the day the better shooting it was. Getting too old for that torture any more....LOL
Course one shotgun is all you need, don`t know why I have 7.