In a stockpot, bring the chicken, water, onion, celery, carrot and 1/2 teaspoon salt to a boil. Reduce heat; cover and simmer for 50-60 minutes or until chicken is tender.
Remove chicken and vegetables from broth. When chicken is cool enough to handle, remove meat from bones; discard skin and bones. Cut chicken into cubes. Chop the onion, celery and carrot. Strain broth and skim fat; set broth aside.
In a small bowl, combine the flour, onion salt, celery salt, pepper and remaining salt. Add 1/2 cup broth; whisk until smooth. In a large saucepan, bring 3 cups broth to a boil; whisk in flour mixture. Cook and stir for 2 minutes or until thickened. Remove from the heat; add chicken and vegetables. Transfer to a 9-in. deep-dish pie plate.
To finish, roll out pastry to fit top of pie. Cut a piece of carrot into a triangle and place in the center of pie. Gently place pastry over pie; trim and flute edges. Cut eyes, mouth and scars into pastry; thread rosemary leaves for stitches.
Cover edges loosely with foil. Bake at 400° for 40-45 minutes or until golden brown and filling is bubbly. Let stand for 15 minutes before cutting.