Chipotle Mexican Grill used to be, but no longer is, partly owned by McDonald’s. It runs 700 restaurants nationwide — with plans to roll out 125 more this year — and is considered one of the nation’s fastest-growing “casual dining” chains. And it seems earnestly interested in sourcing ingredients from small- and mid-sized farmers near its outlets.

At its shop in Charlottesville, Va., the Washington Post reports, it’s been buying pork from Polyface Farm, an operation legendary in sustainable-ag circles for its innovative multi-species rotational grazing system. Polyface and its farmer, Joel Salatin, were immortalized in Michael Pollan’s Omnivore’s Dilemma.

According to the Post:

This month, Chipotle hopes to serve 100 percent Polyface pork in Charlottesville. But that success comes after 17 months of complex negotiations and logistics, including buying extra cooking equipment, developing new recipes, adjusting work schedules, and investing in temperature-monitoring technology for Polyface’s delivery van.

Chipotle — which the Post reports as buying a jaw-dropping 5 millions pounds of pork annually — already sources “naturally raised” pork from Niman Ranch, which buys mainly from family farmers in Iowa and distributes nationally. The Polyface deal represents an experiment in local/regional sourcing.

There were certain, um, cultural obstacles to overcome. For example, individual Chipotle restaurants don’t have fully equipped kitchens; cooking is done in regional hubs and then trucked out to be reheated in the shops. (A similar situation holds true for public-school cafeterias.) Get this:

The pork for all 67 of its mid-Atlantic restaurants is cooked at a kitchen in Manassas, so Chipotle had to refit the Charlottesville branch to accommodate an oven where the Polyface pork could be braised, plus buy pots, pans, and a cooling rack.

But if the Polyface/Chipotle relationship works out and is replicated, it could be great for mid-sized pastured-meat operations. As the article explains:

[Polyface’s] fine-dining clients and buying club members couldn’t get enough of the chops and loins … But Salatin needed a customer to buy shoulders and legs, tougher cuts that are perfect for braising and wrapping in burritos.

Meanwhile, I know for a fact that the company is looking earnestly for farmers to provide grass-fed milk. After I posted recently on controversies in the organic-milk world, a Chipotle researcher contacted me looking for possible milk sources.

I told her that as long as Chipotle was committed to paying a fair price to farmers — and not merely using them them for marketing leverage — I thought the company could play a constructive role in a nationwide transition to a truly sustainable ag. We’ll see.