yeah so this one’s kinda one of those “depends on the inspector” situations. technically, if you go by NEC (like 2020 or 2023 editions), GFCI is required in outdoor receptacles and in areas with damp or wet conditions — and livestock areas can definitely count as that, especially if there's water troughs, wash down spots, or just general barn funk/moisture going on.
thing is, code books don’t always spell out “barn” or “livestock area” directly — they talk in terms like “wet locations,” “agricultural buildings,” or “where electric equipment is exposed to animal confinement.” that gives inspectors a bit of wiggle room. some see it as a safety must-have, others go, “eh it’s not in the book, pass.”
since your barn’s only a few years old and didn’t have any GFCIs put in, sounds like whoever built it either got a chill inspector or interpreted the code differently. if you’re doing new work though, especially if animals are near the outlets, probably worth throwing a GFCI in — not just for passing inspection, but to avoid fried equipment or worse if stuff gets wet.
short version: not always “required” per the letter, but often expected, and more so if you’re dealing with newer code cycles or stricter AHJs.
