Although no available reports suggest that honeydew and the rinds of cantaloupe are toxic to horses, Marion, we’re not sure about horses' desire to eat the rinds. They don’t contain very much nutritional value or provide an appetizing taste, and equines’ digestive systems are very sensitive. Adding new food substances to their diets can cause digestive upset. Also, in general, treats should only be offered in small quantities each day, as too many can interfere with your pets' normal eating patterns and cause nutritional imbalances. We would recommend you speak with your equine veterinarian about giving these rinds to your horse as a snack.
For more information, you can read our Top 10 Nutritional Tips for Horses.