Rental Housing Journal had a recent article with some tips on how you can manage assistance animals on your property:
What can you do if owners of assistance animals break the rules?
You can take action when residents with assistance animals violate community rules. However, proceed carefully and consult your legal counsel.
Give the resident opportunities to remedy the situation before taking steps to remove the animal.
Send written warnings recognizing that the animal is an assistance animal, and reminding the resident that they must follow reasonable rules of conduct.
If the situation continues, let the resident know that if the problem persists the animal may have to be removed and alternative accommodations will be explored.
Document disturbances or damage in writing and with photographs if possible. Phone or in-person conversations will not be as useful as written documentation if you find yourself in legal proceedings.