In a large stockpot, place chicken, quartered onions, 1 carrot, celery and salt.
Add water until ingredients are just covered.
Bring to boil.
Reduce heat to simmer and skim off any impurities that rise to the surface.
Simmer 2½ hours or until meat is tender.
When done, remove skin and bones from chicken and cut meat into pieces.
Strain stock, discard vegetables and reserve liquid.
Preheat oven to 400°F
Fry bacon until crisp.
Peel potatoes then grate very fine, or purée in a blender.
Squeeze 1 cup of potatoes at a time through a clean dish towel to remove liquid.
Reserve all liquid.
Place drained potatoes in a large bowl. Measure liquid.
Measure out an equal amount of chicken stock then discard potato liquid.
In a stockpot bring chicken stock to a rolling boil. Gradually stir hot stock into potatoes and mix thoroughly until all lumps are removed. As boiling stock cooks potatoes, they will take on a jelly-like appearance.
Season with salt and pepper.
Cover bottom of a well-greased pan with half of the potato mixture.
Arrange pieces of chicken, diced onions, carrots and pats of butter on top, distributing evenly.
Cover with the other half of potato mixture and another layer of onions, carrots and butter.
Top with strips of bacon to form the crust. Bake 2 hours or until a browned crust forms.