Place chicken, onions, garlic, celery, carrots and bay leaf into crockpot and fill with water until chicken is covered or mostly covered.
Cook on high for 2 hours (or low for 4) until chicken is falling off the bone. Remove the whole chicken and let cool in a bowl.
Using a strainer placed over a large bowl, pour remaining crockpot contents into the bowl using the strainer to separate out the solid ingredient from the chicken stock. Measure and return 2 cups of chicken stock to crockpot. Stir in cream of chicken soup, pepper, garlic salt and celery seed. Turn crockpot to high heat and cover.
Shred the cooled chicken, discarding the carcass, and return chicken to crockpot. Add solid ingredients from the strainer back into the slow cooker. Stir gently.
Open biscuit dough and slice each biscuit in sixths. Place in crockpot pointy-side down. Cook on high 55-60 minutes or until all dumplings are firm to touch and are golden brown.
Vent the lid to the crockpot if the biscuits are looking too moist. They are ready when they have puffed and are a light golden brown.Be sure to let the chicken cool enough to handle it without hurting yourself before shredding it.