Place the chicken in a large stockpot. Add the celery, carrot, onion, garlic, lemon, bay leaf, peppercorns and the herb bundle; season with salt. Cover the chicken with water and bring to a boil; reduce the heat to a low, rolling simmer. Simmer 60 to 75 minutes, then cool the chicken in its stock. Strain the stock. Remove the chicken in large pieces from the skin and bones. Cut half of the meat into bite-size chunks. Thinly slice or pull the remaining meat.