More than likely you need a permit. There is also the possibility that Michigan DNR will kill them as their goal is to kill all of them based upon no scientific research. Yet, their goal is to bring in the Trumpeter Swans so they can make more money. Should you not want the swans killed we would suggest that you just ask if it is legal to have them. If not, to contact Bob Knox at Knox Swans and Dog in Illinois or where you bought them to take them and give them a good home. The Regal Swan