Remove and discard skin from chicken. Sprinkle chicken with garlic, thyme, a-d salt. Place chicken in 3 1/2- or 4-quart slow cooker. Pour orange juice and vinegar over chicken.
Cover and cook on low-heat setting for 6 to 7 hours or on high-heat setting for 3 to 3-1/2 hours. Remove chicken from slow cooker; cover and keep warm. Discard cooking juices.
In a large bowl, toss together greens, tomatoes, olives, and feta; divide among serving plates. Slice chicken from the bones, discarding the bones. Top each salad with some of the chicken. Drizzle dressing over salads. Makes 6 to 8 servings.