Place a baking sheet in oven and preheat oven to 425 degrees. Prepare pie crusts as directed on package for two-crust pie using a 9-inch pie plate.
Melt butter in a large skillet over medium-heat. Add onion and saute until softened, about 5 minutes.
Stir in flour and cook, stirring constantly, 1 minute. While whisking pour in half and half then pour in turkey gravy.
Add in vegetables, chicken, rosemary, thyme, and season with salt and pepper to taste. Warm through.
Pour mixture in to prepared pie crust in pie plate. Top with second pie crust. Seal edges and flute if desired. Cut several slits in top of pie for steam to escape.
Bake in preheated oven 30 to 35 minutes, or until crust is golden brown (tent edges with foil to prevent excessive browning if needed.
Recipe source: Cooking Classy