There are hog confinements near us but seldom is there any odor and if there is it doesn't last.  They knife in the manure so it doesn't set on top and evaporate into the air.  I saw them with a hose attached to the lagoon and the other end to the device that knifed into the ground.  Never has a chance to be exposed to the air.

Maybe the area in question needs to have some regulations enforced. 

I've seen incinerators for dead pigs or they are picked up on a regular basis, never would you see them laying around and  attracting buzzards.