Spray 5-quart slow cooker with cooking spray. Spray 12-inch skillet with cooking spray; heat over medium-high heat. Add sausage; cook about 3 minutes, stirring occasionally, until browned. Place sausage in slow cooker. Add remaining ingredients except chicken and rosemary sprigs; mix well.
Cover; cook on Low heat setting 7 hours 30 minutes.
Stir chicken into stew. Cover; cook 30 minutes longer. Garnish with rosemary sprigs.