The nice part about a shotgun is that you can tailor the load to the situation. #8 shot for birds or people you really, really don't like, but want them to live to know it, maybe, to #4 shot that puts a stop to lots of problems but won't penetrate a standard house wall from any distance, to slugs, that will drop deer from 50 yards.
I'd go with 12 Gauge, too. I load mine with #2 and #3 shot generally. I'm fairly serious about solving problems. If I shoot that in the house, there's no way it's going to make it to the neighbor's house.
/johnny
I agree with Johnny.
Shot isn’t a problemo but, slugs will over penetrate. However, not the same penetration as a jacketed round, which is harder than a lead bullet.