Step 1Heat the oven to 425 degrees. Finely chop the chile(s) with at least half their seeds (keep all the seeds in if you want the chicken spicy). Scrape the chiles into a large bowl and stir in the thyme, allspice, pepper and ¼ cup olive oil to make a marinade.
Step 2Cut the chicken into 6 pieces: 2 drumsticks, 2 thighs and 2 breasts with the wings still attached; discard or save the bones for making stock. Season the chicken all over liberally with salt, then place the pieces in the bowl with the marinade and toss until evenly coated. Let the chicken sit in the marinade for at least 20 minutes at room temperature or in the refrigerator for at least 2 hours or up to overnight.
Step 3Meanwhile, mix the remaining ¼ cup olive oil, the scallions and garlic in a small, cold skillet. Place over medium-low heat and cook, stirring occasionally, until the aromatics soften and flavor the oil but don’t brown at all, about 10 minutes. Remove the skillet from the heat and stir in the lemon juice and soy sauce and season the vinaigrette with pepper to taste. You can make the vinaigrette and store it in the refrigerator up to 3 days in advance; let come to room temperature again before using.
Step 4Arrange the bread on the bottom of a 9-by-13-inch baking dish or similarly-sized roasting pan. Lay the chicken pieces, skin side up, over the bread, then season again liberally with salt. Bake until golden brown all over and the juices run clear when each piece is pierced, 45 minutes to 1 hour, depending on how large the chicken pieces are (see note above).
Step 5Remove the dish from the oven and let rest for 5 minutes. Transfer the chicken to a plate and tent with foil to keep warm. Using a metal spatula or tongs, lift the bread from the dish and transfer it to a cutting board. Chop the bread into 1 to 1 ½-inch chunks.
Step 6Transfer the bread chunks to a large bowl, then add the lettuce to the bowl by tearing the leaves in half as you add them. Drizzle over three-quarters of the vinaigrette and toss quickly to combine. Transfer the bread salad to a large serving platter, then arrange the chicken pieces over the salad, pouring any juices on the plate over the salad too. Drizzle everything with the rest of the dressing and serve while warm.