Amy's Slow-Cooker Chicken and Dumplings

4-5 skinless, boneless chicken breast halves 2 tablespoons butter 1 small onion, diced 1 carrot, roughly chopped 2 celery ribs, roughly chopped 2 cans (10.75 ounces each) condensed cream of chicken soup 2#190; cups (2 full soup cans worth) water or low sodium chicken stock #189; cup instant brown rice 1#189; cups milk 1 package (10 ounces) refrigerated biscuit dough quarters Place chicken breasts in slow cooker; add butter, onion, celery, carrots, soup and water. Cook on low 6-8 hours. One hour before eating, separate the dough into individual biscuits and cut each into quarters. Stir biscuit pieces, milk and rice into slow cooker, pushing biscuits gently into the liquid. Turn cooker to High and cook 1 more hour. Serves four to five.