Boil hen or large fryer for your broth and chicken. Saute onions and celery in butter. Pour this mixture over bread crumbs in a very large mixing bowl. Add seasonings and toss together. Pour enough broth into mixture to moisten. Add beaten eggs and mix together well. Add baking powder, milk, and remaining broth. Mixture should be very slushy. (Pouring point).
Add chicken. Pack tightly into a 5 litre crockpot. Cover and cook on HIGH for 4 hours. Reduce to LOW and cook 4 to 8 hours.