Place the water, parsley, celery tops, salt, bay leaf and thyme in a heavy pan and bring to a boil.
Lower the heat, add the chicken and simmer slowly for 1 hour.
Meanwhile, prepare the pastry; place the flour and salt in a mixing bowl.
Cut the butter into the flour with a pastry blender or 2 knives until the mixture resembles coarse meal.
Add the water and stir with a fork until the dough can be gathered into a ball.
Wrap the dough in wax paper and refrigerate 1 hour.
When the chicken is cooked, drain it and remove the skin and bones.
Cut the large pieces into strips and chop the remainder finely.
Combine the ground chicken with the pork, veal, garlic, onion, eggs and brandy.
Line a pate mold with the bacon strips and add the ground meat mixture.
Arrange the strips of chicken on top lengthwise.
Roll out the pastry and cover the pate.
Brush the top with lightly beaten egg yolk combined with 1 tablespoon cream.
Make a funnel from aluminum foil and insert into the center of the pate.
Bake the pate for 1 hour in a preheated 375° oven.
Lower the oven temperature to 325°, cover the pate with foil and bake 1 hour more.