^^ Exactly. Call them and talk to them. If your horses are taken care of I wouldn't be so concerned. Noone can help that there are crazy folks all around who call authorities over nothing....they DO eventually get a "crying wolf" reputation, and the authorities pay them little attention.
We had the health department called once because of the "odor" of out barn......the cow farmer up the road had just spread manure...and the suburbanites thought it was our horses, so they called. They came, looked around, decided that our barn was cleaner than most houses, and left.