In the first few levels of the game, you will be taught how to care for your horse by Justin Moorland. He will also give you a bucket, hoof pick, and a brush to use.
Dismount and open your backpack. Then click on the item you wish to use, such as the hoof pick, and drag it onto your horse. Do the same thing with all the objects you need to use to care for your horse. If your bucket is empty you can fill it up at a well. If you run out of hay to feed your horse, you can buy it from many of the stores around Jorvik.
Under your horse’s name on the top left corner of the screen you can see an icon appear to tell you when you need to care of your horse. If you feed, brush, water, and clean your horse’s hooves you have completed your horse’s daily care and by doing this every day, it will be a happy horse!
You can only care for your horses in specially designated areas around the island, mostly at stables. If you don’t feel like taking care of each of your horses individually, you can also purchase Stable Care from within your stable for a cost of 7 Star Coins per day. This can be done by clicking on the notice board in your stable and then clicking on Stable Care. You can choose how many days you wish to purchase, and the stable girl will take care of all your horses for that period of time.
Drag the bucket on your horse to give it water.