The mineral buffet. And it works like this:
 It's actually quite simple. As with the lickstone, you hang all sorts of trays in the stall or paddock and fill them with a variety of ingredients. A good example of a basic assortment:
*Celtic sea salt (loose in a bowl or dissolved in a bowl of water)
 *Celtic sea salt (loose in a bowl or dissolved in a bowl of water)
 *Himalayan salt (several different colours).
 Why these three types of salt as a base?
Celtic sea salt contains all sorts of minerals and trace elements in addition to salt (NaCl). So it's a very complete source of substances that shouldn't be missing from your buffet.
Himalayan salt is the cleanest source of salt (NaCl) without any other minerals. It is therefore the ideal counterpart to sea salt. 
Veendrenk is also very rich in minerals. On the other hand, it contains virtually no salt. So it's a perfect third option for replenishing minerals in the body, the difference being that it doesn't add any extra salt. It also has the advantage of having many humus qualities. Wild horses (or horses whose habitat consists of forest soils) occasionally lick humus-rich soils. This is completely natural and the body needs this type of ingredient.
Of course, you can add other types of product to the mineral buffet range. Here are a few examples:

 Green clay
 Mother earth (moederaarde)
 MSM
 Icelandic seaweed
 Diatomaceous earth
 Bentonit

Replenish the empty container each time. This way, you'll see that from time to time, the preference changes according to need. For example, seasonal changes, stress, hormones, hay changes, parasites, growth and physical exertion can all affect it. Some species may be left untouched for weeks or even months, and eaten empty every day. Fortunately, this doesn't matter, as almost all products have an infinite shelf life.
Tip: use only a small quantity of each species. This has two advantages. You need to refill the containers more often, which keeps the ingredients fresh. In the case of seaweed, for example, this is important because it oxidises when it comes into contact with oxygen. What's more, your horse can never eat too many things at once.
It's important that your horse always has access to an unmixed source of drinking water. Never give food containing sugar! This would lead to ‘bunkering’, i.e. the horse would continue to eat even if it no longer needed it, which can be very dangerous and even cause illness.
The buffet is a challenge for some horses. Certainly, horses that are not completely balanced or that are much too short can have teething problems at first. We often find that they want to eat a lot. So at the start, you need to be careful about how much your horse eats. For example, never give him more than he can eat in a day (1 to 2 tablespoons of salt and feathers; for the other ingredients, stick to the quantities recommended on the label). In general, after a few weeks, you'll see that the behaviour normalises because the deficiency has been remedied and the horse understands that he still has access to the supplement.
One last piece of advice - I hope this is a well-known fact, but what's really important is that there should always be enough roughage! When horses are hungry, they often start eating all sorts of things, which can have the effect of emptying the buffet.
Be creative! Create a varied mineral buffet.
 To stimulate foraging behaviour, you can be very creative, constantly moving containers around or changing their contents. It's said that horses prefer to eat these products on the ground, as it's the closest thing to what they would do in the wild. That's why I recommend hanging the buckets in a low position. And from experience, I can also recommend hanging them in a covered area. Otherwise, you run the risk of the rain washing everything away every time.