FAIR OAKS, Ind. — If your image of a pig farm involves barnyards, mud and pails of slop, the Cambalot pig farm would come as a surprise. The first thing you notice upon arriving here — OK, the second thing, after a certain recognizable aroma — is that there are no pigs in sight.

What you see instead are four long, low-slung metal buildings amid the rolling green hills. In a modern pig farm, the animals reside indoors.