Essentially there are two different types of poultry grit available – insoluble or Flint grit, and soluble grit (usually crushed Oyster Shell). They each have certain benefits to your poultry’s general wellbeing, so it's important to know what each is used for and whether you should be supplying them to your hens. Helping to promote digestion in poultry, Supa Flint Grit passes through the bird to the gizzard. Making sure the grit is a suitable size for your bird is extremely important, as if it is too small it will simply pass through the bird with no benefit at all. Suitable for hens, Supa Flint Grit is used to grind down food so that it can be more easily digested.