Toast the fennel seed in a 10-inch cast-iron skillet over medium heat, constantly moving seeds around in pan until they start to turn light brown, about 5 minutes. Set aside to cool in a small bowl. Once cool, grind seeds. Combine with salt, pepper, and chopped parsley in medium mixing bowl. Add the pork and blend thoroughly. Refrigerate for 1 hour.
Set a medium mixing bowl inside a large mixing bowl filled with ice and place under grinder to catch the meat. Using the fine die of a meat grinder, grind about a cup of the pork mixture at a time, depending on your grinder.
Set a half-sheet pan under the stuffer or stuffing attachment. After lubricating the stuffer or stuffing attachment with shortening, load the casing onto attachment, clipping the end with a clothespin. Slowly stuff the meat into casings, trying to avoid air pockets. This should take approximately 5 minutes.
Lay the sausage out on counter and tie off one end. Pinch and twist to form 4-inch sausages. Remember to twist the unlinked section, not the other way around. Wrap in parchment paper and refrigerate for 2 to 3 hours. Store in the refrigerator for use within 2 to 3 days or freeze, wrapped in aluminum foil, for up to 3 months.
To consume: Sauté over medium heat in a 2-quart sauté pan with 1/4 inch of water. Bring the water to boil, put on a lid, and cook for 10 minutes. Remove the lid (the water will evaporate) and continue cooking over medium heat, turning every 2 to 3 minutes until golden brown. Homemade sausage should reach an internal temperature of 150 to 156ºF.