Inside Tractor Supply Co.'s $6B Amazon-Proof Business

Alongside stacks of 50-pound bags of Producer’s Pride Hog Grower pig food and sunshine yellow CountyLine Heavy-Duty Super Spear hay handlers, Steve Barbarick, Tractor Supply Co.’s chief merchant, is rummaging through a bin of weighty grade-5 hexagonal head bolts, the kind commonly used to fasten structural steel. Sure, you could buy similar bolts at Lowe’s or Home Depot and pay for them individually, but at the Tractor Supply in Thompson’s Station, Tenn. they're sold in bulk and cost only $3.69 a pound. And at those other stores you couldn’t pick up a four-pack of Diamond Classic Heeled Horseshoes on the same trip.