Keep your ingredients at 38-40°F (almost frozen) for easier cutting and grinding. Cut the pork and chicken into 1" cubes (or smaller).
In a large bowl, place all ingredients except for the hog casings. Stir to combine. Refrigerate this mixture while you set up your meat grinder.
Using a meat grinder, coarsely grind the mixture. Send the mixture through the grinder slowly, so that you do not create a jam.
After sending all of the sausage mixture through the grinder once, grind it using the coarse grind plate a second time.
You can shape the mixture into sausage patties at this point if you would like. If you would rather have links in casings, refrigerate the sausage mixture while you do the next steps.
Clean your meat grinder thoroughly and set it up for stuffing sausage. I needed to use the largest stuffing funnel for the hog casings. Rubbing the outside of the stuffing funnel with a little oil can help the casing slide on easier.
Remove your hog casings from their packaging and rinse them in cool water. Prepare them for filling as directed on the packaging. For the ones I am using, I had to soak them in cool water for 15 minutes and then untangle a few and cut them into 2-foot lengths. Then I opened one end of each casing I was using and let cool water (from the faucet) run through the entire length. I let water run through each casing I was using three times, and I only rinsed the insides of the casings I was planning to use. After rinsing, I tied a knot in one end of each casing and set them near the grinder on a paper towel.
When you are ready to stuff sausages, slide a casing over the end of the stuffing funnel. I was able to get the casing to fit by gathering it like I would gather pantyhose I was about to stick my toes into, and then sliding it onto the funnel. My grinder recommends leaving 2" of casing overhanging the end of the stuffing funnel, but the directions for your grinder may vary.
Very slowly start sending your ground sausage mixture through your meat grinder. One hand can use the stomper to push the mixture into the grinder while your other hand can help guide the casing as it fills.
After filling a casing, you can make small links by tying off the casing frequently with kitchen twine. Start tying at the closed end of the casing, making sure there is room for the filling to extend to the open end so the casing does not break. Tie off the open end of the casing last.
After you finish filling one casing, tie a new casing onto the machine and continued the filling process. I did not clean out the machine each time I had finished filling a casing.
Once all of the sausage mixture is used, turn off and unplug your meat grinder. I recommend cleaning out your grinder immediately. I was able to salvage an additional 9 ounces of sausage mixture that was stuck to various parts inside the machine. You can press these leftovers into patties, pan fry them, and enjoy them right away. (Yay, snack time!)
Your homemade sausages will not stay fresh as long as the cured sausage you buy in the store. Any sausages that you are not planning to cook within 24 hours should be double-wrapped in plastic and frozen. If you have a vacuum sealer for food, you can use that for your sausages as an alternative to double-wrapping.
Follow the directions on your casing packaging to store the casings that you did not use. For the brand I purchased, I dried the unused casings (the ones where I did not rinse the interiors), repacked them in salt, and stored them in the fridge where they will wait until my next sausage-making adventure.