Cook chicken in boiling water to cover, for 45 minutes or until tender. drain, reserving broth. Bone chicken and cut into bite size pieces. Set aside.
Bring broth to a boil, add frozen vegetables and simmer for 10 minutes. Drain Vegetables, reserving 1 quart of broth. Set both aside.
Put one pie crust in pie plate, fit to bottom and around sides. Trim edges.
Melt butter in large heavy sauce pan over low heat add 1/2 cup of flour stirring until smooth. Cook 1 minute, stirring constantly. Gradually add chicken broth, cook over medium heat, stirring constantly until thick. stir in salt, pepper, Chicken and vegetables; poor into pastry lined dish.
Place remaing pie crust on top and fold edges under and flute. Cut several slits in top to allow steam to escape. Brush with melted butter.