This arguement should be broken into four differant discussions. The first, hunting with a dog in an open area, cornfield and such, the second, hunting with a dog in heavy cover; the third, hunting without a dog in an open area and the fourth, hunting without a dog in heavy cover.
The last is a true test for a shotgunner and his shotgun. You need to carry a shotgun that fits like a glove because you barely have time to snap the gun to your shoulder let alone try and yank a pair of hammers back.