I had the same problem here in Canada. There was a horse only a mile away from me that was starving, and on its last leg.
Everyday I went to check on them, thinking this would be the day that I would see it dead in the field. Everyday I cried, because
no one would help.
I couldn’t get anyone to help, called the vets, called the police, called the human society.
I went up every night at midnight and threw a bale of hay to the horses, always afraid of getting caught, because everyone
said he was a nut case, and not to get involved.
We even went as far as asking to buy the horse, and he said no, he liked it.
One day I took pictures and sent them to the vet, police and human society, and said if someone didn’t come out and do
something about the horses, I would send the pictures to the local news paper, and to let them know that for months, I
couldn’t get anyone to act.
When they got the pictures, they finally came. The horse is still there, but has gained some weight.
Take pictures and send them to your local paper, you don’t have to say they are from anyone, just where they are.
Good luck.