Instructions
Identify every location where your horse has access to acorns. Pastures and paddocks are the areas where you are most likely to find oaks planted. Do not forget oaks planted near the barnyard or fences.
Determine the amount of access your horse has to the acorns in each location. An oak tree in the barnyard where your horse is not allowed to graze does not present the same level of risk as an oak tree in the pasture.
Restrict the horse's access to the oak trees. This may be done by turning the horse out in a pasture or paddock that does not have oak trees, or by putting a fence around the oak trees to keep the horse away from it. In extreme cases, the trees may need to be cut down and removed from the area altogether.
Provide access to more tempting and safer edibles. Horses with plenty of good hay and grasses to graze on are less likely to consume acorns and other bitter and toxic plant matter. Make sure your horse has very little access to acorns and ample access to things that are good for it to eat.
How to Stop Horses From Eating Acorns
Acorns from an oak tree contain tannin that is considered toxic to horses. While consuming the occasional acorn will not harm most healthy horses, repeated consumption of acorns can lead to a condition called acorn poisoning, which can be fatal if it is severe enough and goes untreated. It is impossible to train a horse not to eat acorns, especially if the bitter, unpleasant taste of them is not enough to deter it. As the owner of a horse that wants to eat acorns, it becomes your job to prevent the horse from doing so in order to keep it healthy.