I’ve read a couple articles on this. For those out in actual rural areas, it is probably something that should just be tolerated. There are many agricultural processes that produce bad smells. Like shit filled creeks (which I kind of oddly like the smell of…)
But there are examples where these businesses are close to residential areas and schools. I think that is a zoning issue. I don’t think anyone here would be defending them if the business making smells was like an automotive painter or from handling of chemicals or maybe some sort of refuse processing (hard to think of examples, because zoning laws and environment regulations already limit those sorts of things.)