Place onions, celery, carrots, potatoes, bay leaf, salt, paprika, thyme, and poultry seasoning in the bottom of a large slow cooker. Stir to combine.
Place chicken on top of vegetables. Season chicken with salt and pepper.
Pour chicken broth over everything, cover, and cook on LOW for 8 hrs.
With 30 mins left in the cooking time, shred the chicken and return meat to the slow cooker. Discard bay leaf.
In a small bowl, whisk together corn starch and cold water until smooth. Stir into the stew and cook on HIGH without the lid for 30 mins.
Best served in bread bowls (can reduce/skip potatoes if doing this)