Place the chicken pieces in the base of the slow cooker. Drizzle about 1 Tbsp of balsamic vinegar over the chicken. Add the red cooking wine (optional) around the chicken as well. Gently toss the zucchini, squash, pepper pieces and onion pieces around and on top of the chicken. Season with salt and pepper.
Set the slow cooker on low and cook for 8 hours.
Before dinner, prepare the rice as directed.
Serve Slow Cooker Balsamic Chicken with Spring Vegetables over rice.