Working in batches, place the chicken in a food processor and pulse until coarsely ground, 6 to 8 times. Transfer to a large bowl. Pulse the bacon until coarsely ground, 3 or 4 times. Add the bacon and the butter to the chicken and mix until well blended. Add the apples.
In a spice mill or in a mortar with a pestle, grind the coriander seeds, fennel seeds, and peppercorns to a medium-fi