Preheat oven to 350 degrees F (175 degrees C). Lightly grease 9x13 inch baking dish.

Place the bacon in a large, deep skillet, and cook over medium high heat until evenly brown. Drain on paper towels. Pour remaining bacon fat in the skillet into a bowl.

Using the same skillet, melt the butter over medium heat. Stir in the onions, celery, garlic, and rosemary, and cook until onions are soft and transparent, about 5 minutes. Stir in the reserved bacon fat.

Meanwhile, place the pumpernickel and rye bread cubes into a large bowl. Stir in the cooked bacon pieces, eggs, thyme, sage, pecans and onion mixture, and toss to mix evenly.

Stir the chicken stock and bourbon together in a bowl. Pour the chicken stock mixture over the bread mixture, adding more stock to reach desired consistency. Use your hands to evenly mix the ingredients together. Spoon stuffing mixture evenly in the prepared baking dish and pat down lightly.

Bake for 45 minutes in the preheated oven or until a knife inserted into the center comes out clean. If you wish to have a darker crust on top, bake for an additional 10 minutes.