Preheat oven to 375F.
Place a large, heavy pot over high heat with 2 tablespoons EVOO, 2 turns of the pan. Add the pancetta and cook until brown and crispy, 3-5 minutes. Remove pancetta with a slotted spoon to a paper towel-lined plate and reserve.
Add ground chicken to the pot with the pancetta drippings and cook until lightly browned, about 5 minutes, breaking it up into pieces with a wooden spoon.
Add the onions, carrots, grated garlic and bay leaf to the pot and cook until browned, about 8 minutes more. Season with salt and freshly ground pepper, then stir in the balsamic vinegar, scraping up the brown bits on the bottom of the pot.
While the veggies are browning, puree the roasted peppers in a food processor. Stir the puree into the pot then add the chicken broth, thyme sprigs, chili powder, paprika and allspice, and season with salt and pepper. Bring up to a boil. Once boiling, reduce heat and simmer for 20 minutes, skimming the fat from the surface, if desired.
While the chili is simmering, place a small skillet over medium heat. Add remaining 2 tablespoons olive oil, butter and crushed garlic cloves, and cook 2-3 minutes.
Place bread in a large bowl. Pour the garlic butter evenly over the bread. Sprinkle the reserved pancetta, Pecorino, rosemary and lots of pepper over the bread and toss to coat. Place the cubes on a baking sheet and bake for 15 minutes, until golden and crunchy, tossing occasionally. Remove from oven and let cool.
To serve, remove bay leaf and thyme springs from the pot. Ladle chili bowls and top with a handful of the pancetta croutons.