Marinate pheasant legs with salt, pepper, garlic, thyme, bay, and juniper in the fridge for 6 hours.
Rinse the marinade off the legs and pat dry with a towel.
Heat 600g duck fat to 80-90°C and gently cook legs for 90 minutes until meltingly tender.
Season pheasant breasts with salt and pepper.
Fry breasts in 15ml duck fat for 10 minutes total until medium-rare, then cube.
Sauté onions, herbs, and juniper in the same pan until softened.
Add mushrooms and fry until moisture evaporates.
Mix chestnuts, berries, cubed breasts, and seasoning into the onion mixture.
Deglaze the pan with water and add to the filling.
Crisp the confit leg meat in a pan, flake off the bone, and stir into filling.
Roll pastry to 2mm thick and cut eight 10cm discs and eight 14cm discs.
Place 60g of filling onto each 10cm disc.
Brush edges with egg, seal with 14cm discs, and chill for 15 minutes.
Trim edges, brush with egg wash, score half-moon patterns, and chill.
Preheat oven to 200°C and heat a baking sheet.
Chop the pheasant carcass into 3cm pieces.
Brown carcass and juniper in duck fat, then remove.
Sauté remaining onions, celery, and mushrooms in the pan.
Add Madeira and port, reducing the volume by half.
Add 400ml cold water and simmer for 20 minutes.
Strain sauce, return to heat, and thicken with arrowroot.
Bake pithiviers for 15-20 minutes until golden.
Dry fry garnish fruits and nuts for 3 minutes.
Serve pithiviers with sauce poured inside and garnish scattered around.