Preheat oven to 375°F.
Bring broth to a hard boil in a heavy medium-sized pot over medium-high heat. Add fennel, cook for 5 mins add chicken, carrots, lower to a simmer and cook for 10 minutes. Meanwhile, place pancetta and onions on a baking tray and place in the hot oven for 15 minutes, or until pancetta is sizzling and onions are lightly golden. Set aside.
Strain chicken mixture and reserve broth. In a saucepan melt butter, whisk in flour, and cook stirring for 2-3 minutes. Gradually whisk in milk and cook, whisking until sauce thickens, about 4 minutes. Add fennel seeds and season with salt and pepper to taste.
Add chicken and pancetta mixture to sauce and divide between 8-10 ounce soufflé dishes.
Roll out chilled dough on a lightly floured surface to about 1/8th inch thick. Cut out 8 rounds, each measuring 1 inch larger in diameter than the soufflé dish. Reroll excess pastry to cut out 8 leaf shapes. Place a cut-out round over each soufflé dish and press dough overhang to the sides of the soufflé dish. Brush on egg wash and place cut-out leaf in the center of the pastry, brush leaf with egg wash. Cut 2 small slits for steam to escape.
Place soufflé dishes on a baking tray and bake in the oven for 40 minutes or until pastry is golden.