In large plastic or paper bag, coat chicken with flour in 2 batches, shaking off excess. Place in single layer on wax paper.
Warm 3 tablespoons of the oil in 8 litre Dutch oven over medium heat. Add chicken in batches so pan is not crowded. Cook 15 to 20 minutes per batch, or until browned on all sides. Remove to large plate.
Warm remaining 1 tablespoon of oil in same pan over medium heat. Add leeks; cook 5 minutes, or until lightly browned, stirring to scrape up brown bits. Add carrots, celery and apple wedges; cook 4 minutes. Add browned chicken, broth, juice, dill, salt and pepper. Cover; bring to a boil. Reduce heat and simmer 15 minutes.
While chicken cooks, make dumpling batter (recipe follows).
Dumplings: Mix 2 cups Bisquick and two third cup milk until soft dough forms. Drop dough by spoonfuls onto stew (do not drop directly into liquid). Cook uncovered over low heat 10 minutes. Cover and cook 10 minutes longer.