Do horses like eating apples and why?

Most of them do, but it really depends on the horse.

One may eat them until there is no more, while another could shun it completely. They also like carrots and, if used very moderately, peppermints. But you should check with your vet before ever feeding a horse anything strange like people food.

Just to improve this answer a little, you can give your horse a Apple now and again but it not recommended to give him/her more the 2 a day. Apples as you know contain acid, this could cause problems for the horse in his/her's stomach so its recommended you keep a close eye on how many you or someone else is feeding Apples to your a horse.