Spray the inside of a large slow cooker. Break the layers apart on 2 of the onions and scatter in the bottom of the slow cooker. Layer the chunks of carrots and potatoes on top of the onions. Add 2 of the garlic cloves, and 2 sprigs of rosemary, 2 sprigs of sage and 4 sprigs of thyme.
Place the chicken inside the roaster with its legs and empty cavity up. Sprinkle the black pepper inside the chicken cavity, add the remaining sprigs or rosemary, thyme, and sage. Fill the cavity with the remaining onions and garlic. Pour the soy sauce inside the chicken cavity.
Place the chicken, breast side down on top of the vegetables, cover and cook for 5-6 hours or until a thermometer that is inserted into the thickest part of the meat reads 165 degrees F. Do not over cook the chicken.
Remove the chicken to a platter, breast side up and cover with foil and allow to rest for 20-30 minutes.
If desired strain the broth from the vegetables and allow to settle, skim off the fat. Use to make gravy if desired or serve as broth over the vegetables.
Place the vegetables around the whole chicken (or cut into pieces if desired) on the platter and serve family style. Serve with warm broth or gravy.
