Chicken and sage are a pretty brilliant combination. Even better when you add a little something-something with... pork fat! Yep, more animal fats. More clogged arteries. More deliciousness. Can't say I don't push the fatty boundaries.
But seriously, just mincing up chicken will surely lead to Dry-Town Chicken Mince, population: You. It needs more moisture than chicken fat alone can deliver, so the pork fat is just providing a little bit of a helping hand. A nudge in a tasty direction. Nothing bad can come of this.