My hog houses are within 4ft of my lawn and they don’t seem to mind the sound of my electric mower too much; I’ve had one in residence all summer so it’s either deaf or happy! Next door did disturb one with his motor mower once as I saw a hog scarper across my garden to one of my hog houses whilst he was mowing, but it’s a very, very LOUD mower! It has since moved back next door though.
They do get used to familiar noises once they realise there isn’t a threat with it. At the beginning of hog season they get spooked by the sound of my back door opening but within a couple of weeks they’re totally cool with it.
