Preheat oven to 250°F. Chop the bread into small cubes. Add 12 cups (1lb) of bread to two baking sheets in a single layer. Bake the bread crumbs for 45 minutes, and toss halfway through. Set aside.
To Make Stuffing:
Preheat oven to 350°F. Grease a 9×13 casserole dish with nonstick cooking spray or butter.
Add ½ cup butter to a large pot. Add 2 cups diced onions and 1 ½ cups diced celery to the pot and cook until softened. Add onions and celery to the large bowl with bread crumbs.
In a separate medium bowl, add 2 ½ cups chicken broth, 2 large eggs, 3 tablespoon chopped fresh rosemary, 2 tablespoon chopped fresh sage, 2 tablespoon chopped fresh thyme, 1 teaspoon salt and ½ teaspoon black pepper to a bowl. Mix together, then pour over top of the bread crumbs and toss everything together.
Pour into the greased casserole dish. Cover with foil and bake 40 minutes. Uncover and bake an additional 40-45 mins.