Hogs are not easily distracted when rooting around, especially in groups, the noise they make and the movement of the others can conceal the fact that you are there.
I have inserted the magazine, released the bolt and removed the safety of a mini14 (not the most stealthy of operations) in fairly close proximity to hogs and the didn't flinch.
When the shot goes off that's a different story.
Navin R. Johnson: "He hates these cans!!!! Stay away from the cans!!!!"