Place bread in a food processor; pulse 2 times or until coarse crumbs measure 1/2 cup. Combine breadcrumbs, lamb, and next 5 ingredients (through egg) in a bowl. Shape into 36 (1 1/4-inch) meatballs.
Heat a large nonstick skillet over medium-high heat. Add one-third of meatballs; cook 1 minute, shaking pan to brown on all sides. Transfer meatballs to a 3 1/2-or 4-quart slow cooker. Repeat procedure twice with remaining meatballs.
Combine chutney and next 4 ingredients (through chopped mint) in a bowl; pour over meatballs. Cover and cook on LOW for 2 hours. Serve meatballs and sauce over couscous. Sprinkle with thinly sliced mint.
To ensure that you get a lean product, ask the butcher to grind a lean boneless leg of lamb.