You will need a grater, a large pan (17"x12"x2"), and a sturdy cloth bag.
Simmer the chickens in a pot on top of the stove with plenty of onions and seasonings. When cooked, separate the meat from the bones and chop meat into pieces. Save the broth.
Meanwhile, peel the potatoes and soak in cold water. Grate about 10 potatoes at a time and then place them in a cloth bag.
Squeeze tightly until all the water and starch is removed. Do all the potatoes this way. Save the liquid from the potatoes: measure it. You must measure an equal amount of chicken broth to replace the potato water. When the potatoes are all squeezed, loosen them in a large pan and gradually add the measured chicken broth, stirring slowly. The potatoes may take on a jelly-like appearance. Be sure there are no lumps. Add seasonings and stir very well.
Mix the potato mixture, chicken pieces and chopped onion all together in a large, well-greased roasting pan. (Some people prefer to arrange in layers, either is fine). Top with several pats of butter.
Place pie in a hot (400║ F) oven for about 2 hours, or until a brown crust is formed.
Note: Some people like to lay strips of bacon across the top to form a crust.