Wash chickens and pat dry. Heat butter in a large skillet and saute onions until soft and light yellow. Lay chicken pieces over onions and saute. Simmer, covered, over low heat for about 45 minutes. When chicken is tender, remove and keep warm. Stir flour and salt into onions. Gradually stir in chicken stock. stir over low heat until thickened. Remove pan from heat and mix paprika into liquid. Amount depends on taste and color desired. Blend in sour cream. Add chicken to sauce. Spoon sauce over chicken. Reheat but do not boil. Serve with noodles or dumplings. Makes 6 servings.