You don't feed it to them. You go on the black market, click the golden apple, select the howrse, then the coat, then "confirm".
Hope this helps!
-Kатнячп•Fυııэя
You can only give apples to other people's horses.
Feed your horse every day or your horse will die.
You feed your horse by clicking the feed link to the top left of his page and selecting the amount of forage and grains to give.
To raise your horse's energy on Howrse, you can feed him treats such as a turnip or carrot, stroke him, feed, and let him spend time in the pasture or box.
When you click the button to feed your howrse, it will indicate how much fodder it needs.
You will need to feed the horse and donkey either a Golden Carrot or Golden Apple. A baby mule will be born between them after they are done breeding. To make a Golden Carrot, you will need to place one carrot in the center with Gold Nuggets surrounding it on the Crafting Table. The crafting method is nearly the same for the Golden Apple, but instead of nuggets, they will need to be replaced with Golden Ingots.
Horses are fed hay and oats as a stable diet.
Feed ur horse an apple, stroke them, and Groom them once a day. Eventually their morale gets really high!
You feed the horse the most allowed amount, in hope to get it back to it's original weight. You will have to check back everyday, or over feed the horse if you won't be on every day
Put it in a hollowed out apple, or in their feed
You have probably already done so.
Go to the feed button on the horses page and it will say it.