wtnhunt, yep deer can get internal paraseites just like other grazing animals. They rarely ever cause a problem in deer b/c they are free roaming. Where as cattle and sheep are usually in a confined area they are constantly reinfecting themselves--therefore they need to be on a deworming program. I imagine that deer that frequent pastures where other domisticated ruminants live they probably do have a few worms. But since they are free roaming they aren't constantly reinfecting themselves with the worms.

hope this answers your question!
todd