In a large, heavy pot, heat 1/4 cup EVOO, 4 turns of the pan, over high heat. Add the chicken, season with salt and pepper and cook until lightly browned, about 5 minutes. Add the onions, carrots and bay leaf and cook until browned, about 8 minutes more. Stir in the balsamic vinegar, scraping up the pan drippings. Remove the pan from the heat.
In a food processor, puree the roasted peppers, then stir into the pot. Throw in the thyme sprigs, chili powder, paprika and allspice; season with salt and pepper. Add the chicken broth, bring to a boil, then reduce the heat and simmer for 20 minutes, skimming the fat from the surface, if desired.
Preheat the oven to 375 degrees . In a small skillet, heat the remaining 1/4 cup EVOO, 4 turns of the pan, over medium-high heat. Add the pancetta and cook until browned, 3 to 5 minutes. Using a slotted spoon, transfer to a small plate. Add the butter to the skillet and turn off the heat.
Place the bread and garlic in a large bowl. Pour the butter mixture evenly over the bread. Sprinkle the pancetta, cheese, rosemary and lots of pepper over the bread and toss to coat. Place the cubes on a baking sheet and bake until golden, tossing every now and again, about 15 minutes. Let cool.
Discard the bay leaf and thyme sprigs. Serve the chili in mugs and top with the pancetta croutons.