Coastie

Try this:
It conveys a reasonable sense of caring and cooperation and offers no threat to either the animal owners nor the animals, it also puts you on record as being concerned for the safety and well being of these pets and puts the responsibility on the owners.

Good luck

Dear Neighbor,

While visiting property that I lease in the area , I have noticed a number of pets and livestock roaming loose and unattended. I am greatly concerned for the safety and well being of these animals as there are so many things that can happen to them. Horses and dogs in particular are suceptible to accidents involving automobiles, theft and malicious individuals bent on harming small animals.

Please insure that your animals are properly fenced or restrained to assure their continued well being. If you require assistance in building or maintaining a proper enclosure for your pets and livestock, I would be happy to assist you in constructing or repairing your fence or pen if you supply the material, I will provide part of the labor.

Sign with your name and contact info.

CC: Local Law enforcement
CC: Local Newspaper Editor
CC: Local Humane Society