1. Immerse pork casing in a large bowl of cold water; refrigerate overnight.

2. Hold one end of each piece of casing up to the nozzle of the faucet and support it with your other hand; run cold water through the soaked casings to check for holes and begin to open it out, so it will be easier to stuff. If there are any holes in the casing, cut out that piece. Keep casings in a bowl of cold water until ready to stuff.

3. Transfer chicken and pork to freezer until exterior of the meat is brittle and hard on the outside but still soft in the middle, 30 to 60 minutes. Do not freeze solid. This is called open-freezing. (It is not necessary to distribute the meat evenly so it's not touching other pieces; the meat on top will freeze first, and that will be enough to lower the temperature for the whole batch.) When making sausage, meat must stay at or below 45 degrees at all times during the process. The ideal temperature is 38 degrees.

4. Make sure all equipment is very clean and place in refrigerator or freezer to chill. This should include bowls, grinding equipment, and stuffer.

5. Cut meat into cubes that are smaller than the opening of the meat grinder (about 1-inch cubes). Open-freeze meat, 30 to 60 minutes.

6. In a medium bowl, mix together salt, thyme, sage, parsley, pepper, fenugreek, and red-pepper flakes; set aside.

7. Fit clean, chilled grinder with a medium clean, chilled die. Grind meat, starting with pork. Start rotor, and, without using the supplied pusher, let rotor grab each cube of meat and bring it forward toward the blade and through the grinding plate. Continue grinding until both the pork and chicken are ground. Transfer to a clean, cold, nonreactive bowl and open-freeze until surface is crunchy, 30 to 60 minutes.

8. Whisk apple, ice water, calvados, and honey into salt mixture until well blended and dry ingredients have dissolved; set aside.

9. In a large, wide basin or bowl, combine cold meat with the apple mixture. Using very clean hands, begin kneading and turning the mixture as you would a large quantity of bread dough. Mixture should become creamy, caused by the warmth of your hands; this indicates that the mixing process is finished. Remove a few tablespoons of meat mixture and set aside. Transfer remaining meat mixture to refrigerator.

10. Heat a small nonstick skillet over medium heat; add reserved tablespoons of meat mixture to skillet and cook until cooked through. Taste, and adjust seasoning in remaining meat mixture as necessary.

11. Prepare a very clean sausage stuffer. Place bowl of casings, in water, next to stuffer. Line baking sheets with parchment paper; set aside.

12. Working in batches, transfer sausage mixture to the hopper of the sausage stuffer, compacting it very lightly with a spatula to be sure there are no air pockets; cover with lid. Thread a length of casing all the way into the stuffing horn and start cranking, just to move a little sausage into the casing. Stop, and crank backwards slightly to stop the forward movement. Pinch the casing just where the meat starts, to exclude all the air; tie in a knot.

13. Start cranking again with one hand while you support the emerging sausage with the other. Move the casing out slowly to allow it to fill fully, but not too tightly; there should be some give in the sausage when it comes to tie the links. When you get close to the end, leave 6 inches of unstuffed casing and stop cranking.

14. Working from the original knot, measure 4 inches of sausage. Pinch sausage firmly to form your first link; twist forward about seven rotations. Move another 4 inches down sausage; pinch but do not twist. Repeat process as you move down sausage, alternating pinch-and-twist links with pinch-only links. Twist the open end right at the surface of the sausage to seal off entire coil. Repeat entire process with remaining sausage mixture and casing.

15. Cook immediately or hang or place sausages on parchment paper-lined baking sheets in refrigerator overnight covered with plastic wrap. Cut between each link before cooking. Do not prick sausage before cooking; cook slowly and gently to prevent bursting. Only prick if you see air holes.