There are many variables in the question.
[ul][*]12 ga. or 20 ga.?[*]12 ga., I use less shot, because it has more shot. 20 ga., more shot because less.[*]If you are hunting with dogs: I would suggest something a larger shot because they will be usually moving. I would suggest 7 1/2's or 6's.[*]If your are hunting without dogs and stalking: Use very little shot. They will be sitting still if anything a few hops. A .22 would even be a good choice for this. 6's at most.[*]If you are hunting without dogs and jump shooting: Same as with dogs, they will be moving. More shot because of speed. I would suggest 7 1/2's or 6's.[/ul]