The deer that runs through camp is a reindeer. Reindeer are not found in Wisconsin. In Wisconsin, whitetail deer are hunted.
Several characters remark about how delicious the birds Fez caught were, until they realize the birds were crows, which bothers them on superstitious grounds. However, in real life, they would not have thought the crows tasted good at all. Crows are known for tasting awful, to the point that there's an old outdoorsmen's joke that to prepare a crow for eating, you boil it with a boot, then eat the boot.
There is no recoil from the rifle when Red and Eric fire.
Deer hunters wouldn't wear brown into the woods, even in the '70s. Those who did were often mistaken as deer. Red/black checkered wool coats were often worn, as well as dark colored coats similar to Eric's.