Place the chicken, butter, soups, broth, seasoning and onion in a slow cooker, and fill with enough water to cover.
Cover, and cook for 5 to 6 hours on High. About 30 minutes before serving, remove the chicken breasts and shred on a plate. Return to the slow cooker.
Heavily flour your work surface. Take the biscuits out of the containers and roll them out into thinner pieces on the flour. Cut into strips 1/2 inch wide and place in the slow cooker, making sure that the dough is submerged in the liquids to cook. Cook until the dough is no longer raw in the center, around 30-40 minutes.