In your slow cooker, whisk together the apple jelly, apple juice, water, balsamic vinegar, chicken bouillon, garlic power, salt, thyme, paprika and pepper. Add the chicken breasts, turning once to coat.
Set the slow cooker to high for 3 hours.
Melt butter in a small bowl, whisking in cornstarch. Stir into slow cooker mixture to thicken the sauce. Continue cooking on low for 15 minutes.
During the final 10-15 minutes of cooking, prepare the orzo pasta according to package instructions.
Serve hot over orzo and garnish with fresh parsley.