Preheat oven to 375°. Remove giblets and such from cavity of bird and discard. Rinse inside cavity and let dry completely.
Loosen skin on breasts and legs with fingers. Rub salt and pepper all over the chicken and under skin on breasts and legs. Arrange 3 bay leaves under the skin on one breasts, in a decorative design. Repeat on other side and under the skin of legs.Place remaining leaves in cavity of chicken.
Tie legs with twine and tuck wings under chicken. Arrange celery, carrots and onions in roasting pan in a single layer so that chicken can roast on them.
Place chicken breasts side down on vegetables and bake at 375° for 35 minutes.Turn chicken breasts side up.Increase heat to 450° and cook for 25 minutes longer. Watch that chicken doesn't burn. Check internal temperature to 170°.
Remove chicken to cutting board and let stand for 15 minutes before carving. You can serve chicken with the carrots and onions or discard all vegetables.I think this chicken will be juicy and flavorful without a gravy. However, if you want a gravy; bring pan drippings to a simmer in a saucepan. Make a slurry of 2Tbs. flour and 3 Tbs. water. Stir slurry into simmering drippings until clear and thickened.