Rarely, a hog will show its face, flank, foot, etc., grotesquely twisted, pock marked, oozing, etc. It has been rattlesnake bitten...and deeply - but survived and the poison is literally rotting the hide off of the animal.
Ordinarily, a 40+pound hog can take a snake bite and its blubbery hide is tough enough to either deflect the bite or the poison remains in the fat and does no harmful effect.
As omnivores, hogs will eat just about EVERYTHING they can get into their mouths. They will root out a den of snakes using their higher sence of smell to find them. Hogs have no compunction in eating a snake on the prowl either. The musky smell of the snake is a give-away to the hogs.
I used to have more snakes. Garter, King, Coachwhip, Green, Cottonmouth Moccosin, Timber rattlers, Pigmy rattlers, Eastern Diamondback rattlers, Coral Snakes, Indigo and others. In twenty years of land ownership and countless MONTHS of DAYS afield, I have only seen three Diamondbacks of appreciable size (>5-feet). Dave shot two of those and one of them (~6-feet) attempted to mount the running lawn tractor with me sitting in the seat. I "discouraged" him with my 1911 Auto-Ordnance in 45 ACP.
I suspect the hogs keep the snakes well thinned in my location.