That’s horrible that someone dumped nails where the horses and humans would walk. When we would ride horses on the trails by us, a housing development went up and one of the driveways crossed our trail. The owner put up cement blocks, but the horses just stepped right over them. Next time we went, they had put broken glass down. We rode up along the property a little bit, and then cross where there was no glass. The owner came out screaming. I’m calling the cops. There was no need to call the sheriff for that--one of our party was a mounted sheriff. She turned her horse, so that person could see the chest plate that said P county mounted police.
Fun fact about New Jersey, not only do horses have the right of way at all times. They also have the right to trespass on your property.