Season the chicken with salt and pepper. Grill or broil 5 to 8 minutes or until cooked through. Set aside to cool.
In a large bowl, combine the cooled chicken, lettuce and parmesan. Stir in the salad dressing. Refrigerate until ready to serve.
Cut the loaves in half crosswise to form 4 loaves. Hollow out the loaves leaving about 1/2 inch border on all sides. Toast the loaves in the oven until slightly crispy and warm on the insides.
Spoon the salad mixture into the bread. Serve immediately.