Problem is, that would take a lot of time and also, I believe the Geneva Convention doesn't allow for anything to be implanted into a POW. Whether the government calls them POW's or not is really besides the point seeing as how they were captured during a war, which I do believe would make them prisoners of war.
Also, one things humans have over animals is the ability to lie and be very cunning. Suppose a single terrorist figures out he's being tracked and decides to act like he's going to meet up with his Cell but instead goes somewhere else and we attack innocent people?
It's an interesting thought, but in my opinion, it leaves too much to chance.
Also, as was mentioned, this would seem to border on testing things on people, which wouldn't make us look like the "Better" or "Morally Superior" people.
Take care all.
