I use the Hi Mountain Summer Sausage kit because it works and it always makes a consistently great product. These instructions show the little things I've added over the years to take it up an extra notch.
Grind venison, bacon, and chicken breasts through a course plate and place in large plastic mixing tub.
Place sausage casings in bowl of warm water to soak at this time, also make sure to have some twine on hand to tie the open ends off.
Pour in all dry seasonings, cure, garlic powder, and peppers over the ground meat. Then top with cold water. Mix thoroughly by hand for at least 15 minutes and make sure all seasoning is mixed in and the three meats are now homogeneous. The venison will be a dark red, the bacon a light pink, and the chicken all white starting out. When it is a uniform medium red the mixing is complete. I've found that the 2 lbs of bacon and chicken add just the right amount of fat content to the deer that it will still preserve well, but it doesn't get dried out after opening a roll and putting it back in the fridge.
(I make my own homemade chipotle powder as well. I smoke assorted hot peppers out of my garden in the summer and then dehydrate them for a couple days. Then I grind them into pepper flakes with a food processor. They keep for a couple years if dried out all the way and then placed in an air tight container.)
Stuffing the sausage in casings is a 2 person job no mater how you do it, so make sure you have a friend handy. Add the sausage tube to the grinder and slide the casing over to fill while the 2nd person feeds the meat mixture into the machine. Make sure to use a firm grip as the casings are filled, this makes the meat pack in nicely and keeps out air bubbles. When a casing is about an inch and a half from the end, stop, twist, and tie off the end of the casing with the twine. Once all the casings are filled, place in the refrigerator for about 24 hours to cure.
On the next day remove the sausages from the fridge and allow to warm up while you are making your smoker fire. I use a combination of charcoal and oak for the main fire and then add some hickory to add flavor to it. Apple wood works great for this too if you can find it available. Fill the water pan 3/4 full and then add a beer to top it off. Make sure any lighter fluid is burned off and that it is smoking cleaning before adding the sausages. Hang them from the top rack and make sure there is clearance between them and the water pan. Leave in the smoker for about 4 hours and check the temperature. My little smoker doesn't burn very hot, so I always end up pulling them and finishing them off in the oven at 325 for 30 to 40 minutes at the end. They are done when they reach an internal temp of 155 to 160.
Allow to cool, and then wipe each sausage down with a paper towel and wrap in plastic wrap. Once cured and cooked they will keep in the fridge for 2 to 3 weeks if they last that long. 15 lbs of meat at one time sounds like a lot, but some how all my friends and neighbors find out every time I make this and then it is gone before I know it.