In a slow cooker, combine chicken, onions, garlic and chicken stock. Cover and cook on high 3 to 4 hours, until it shreds easily. Remove the chicken from slow cooker, save 1/2 cup stock and discard the rest. Shred the chicken and place back in the slow cooker with the reserved stock and the hot sauce. Cook for another 30 minutes.
Lay out lettuce and top with desired amount of chicken then top with shredded carrots, celery, blue cheese and dressing.