The pie is designed to be presented at the table as a glorious hand raised pie that’s heavily decorated. Inside is a big bird, stuffed with a smaller bird etc etc – think of it as an edible Russian doll covered with elaborately decorated pastry.
The Art of Cookery by Hannah Glasse (1740) gives a recipe for the pie using ‘whatever sort of wild fowl you can get’ alongside four pounds of butter and four bushels of flour for the pastry – which seems like rather a lot to me.
Harewood House used a recipe in the nineteenth century that involved a goose as the largest bird.
The Yorkshire pie may also be described as a stand pie because the pastry crust is hand raised.
For further information on Yorkshire pies follow here: https://countryhousereader.wordpress.com/2014/12/24/yorkshire-christmas-pie/
Pies with elaborate crusts have been served at feasts since medieval times.