For the past several years, whenever Tractor Supply's CEO Jim Wright spoke about his company's earnings, he usually described a strong performance in a challenging environment — a 1,000-plus-store little engine that could.

Last month, his replacement, Greg Sandfort, picked up where Wright left off, pointing to a 10.8% fourth-quarter sales increase and a 24% increase in net income. In his first earnings call as CEO, Sandfort ran analysts through the Brentwood, Tenn.-based retailer's challenges and opportunities.