Put the chicken in a large pot and cover with water. Bring to a boil, reduce heat to medium, cover and cook until the meat falls off the bones.
Take the chicken out of the pot and port the broth through a strainer into a big bowl. (You will use this to make your gravy.).
If you want potato and veggies in your pie, pre-cook them (except frozen veggies - just thaw them or they will be mushy).
Put a pie crust in a pie pan. Lay pieces of chicken on the crust (about 4c of chicken). Put the potatoes and any veggies on top of the chicken.
To make the gravy, melt the butter in a saucepan. Add flour and whisk until smooth. Slowly whisk in chicken broth. Cook over medium high heat until thickened, whisking frequently. Add salt and pepper to taste.
Pour gravy on top of the chicken and veggies. Put on the top crust and crimp the edges and cut a few small vents in the top of the crust.
Bake for 25-30 minutes in a preheated 425 degree oven, until the crust is golden brown.