Kinger it seems your describing two different types of sausages? Country style is usually a breskfast sausage with natural or collagen casings and summer sausage is fibrous casings. Is that what your refering too? My rough guess off the bat on your summer sausage cojld be 1 that it wasnt mixed as well as it should have been so the meat didnt bind fully togeather. But i think the main reason is the internal temp of the sausage got too high. This could be because it wasnt fully cooled down after pulling it out of the smoker. Once you pull it out of the smoker the temperature rises very fast and can over cook your sausage and cause it to stick to the casing very badly. Did you monitor the temperature of the sausage after you pulled it? Also what was the internal temp when you pulled it? On the country style i would need more information on type of casing and how you cooked it.

Generally any of those sausage seasonings such as hollys medium would be a great fit for venison. Typically on breakfast style sausages I add a small amount of red pepper flakes which add a nice touch for venison. Make sure to add between 20% and 30% pork fat (back fat works great). Also for your grind use the course plate and run it through twice. A small amount of water will help with meat spice mixing and grinding. Just make sure to add the water after youve mixed in the seasonings a bit so you dont get clumping.