I have mixed the flour and salt in a bowl and put it in the freezer as well. having all the ingredients very cold is the key to making this butter crust.
In a large bowl, combine flour and salt. Cut in butter with pastry blender until mixture resembles coarse crumbs. Stir in water, a tablespoon at a time, until mixture forms a ball. Wrap in plastic and refrigerate for 4 hours or overnight.
I've never waited 4 hours for it to refrigerate, 2 hours is the longest refrigeration time I've ever given the dough before using it the same day. I have made it and placed it in the fridge overnight to use the next day or two.
Roll dough out to fit a 9 inch pie plate. After the filling has cooled , place the crust over the filling, crimp and bake at 375 degrees for 35 - 40 minutes or until lightly browned on top. let the Chicken Pie cool 10 - 15 minutes before cutting and serving.