Mix soy sauce, honey, garlic, ginger, and pepper in small bowl or measuring cup.
Place the chicken in a large, gallon-sized freezer bag. Pour marinade over chicken.
Add broccoli, cauliflower, carrots, and red bell pepper to freezer bag. Seal freezer bag and ensure excess air is squeezed out. Gently mix contents together so that the marinade fully coats the chicken.
Place in freezer and store up to 3 months.
When ready to enjoy, thaw completely and pour contents into slow cooker.
Cook on low for 6 hours, or high for 3 hours, or until chicken is fully cooked.