Grit in captivity
In the wild, herbivorous birds mainly eat plant-like material and/or seeds. To be able to digest this, the seed hulls and plant cell walls must first be destroyed in the gizzard. Naturally, birds often consume small non-digestible pebbles for this. As an alternative to these stones, insoluble grit is fed . In captivity, birds are mainly fed easily digestible pellets instead of plant-like material and/or seeds. As a result, these birds have little or no need for insoluble grit. In addition, birds can also take in stones themselves if they are (partially) kept outside. For birds in captivity that do eat a lot of plant-like material and/or seeds, it is recommended to add insoluble grit.
Birds that are fed pellets are generally provided with sufficient minerals such as calcium. However, there are a number of birds that have an extra need for calcium, such as growing birds and laying birds. In these situations, soluble grit is often supplemented. Special pellet diets with a higher percentage of calcium are also available for these birds. Research has shown that birds have the capacity to self-regulate their calcium intake. So they will not quickly absorb an excess of calcium. It is therefore recommended that a small percentage of the diet consists of soluble grit. This is also part of the diet of many birds in the wild. There are different types of soluble grit such as sepia, oyster shell, limestone (calcium carbonate), marble (crystalline limestone) and gypsum (calcium sulfate).