Grit

If chickens are on a diet that contains a lot of larger sized grains or food particles, they need to have some small rock chips or pebbles (insoluble grit) in their diet to help the gizzard grind everything into a more digestible form.

This is because chickens don’t have teeth and swallow their food whole without chewing.  Birds that don’t have any grit in their diet may need up to 20% extra feed because they are not digesting things as effectively.

This section will cover the best ways of providing grit for your birds.

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Types of Grit

There are two main types of grit:

  • Soluble grit: Usually in the form of oyster shells or limestone chips that will dissolve during the process of digestion. These can also provide a good source of extra calcium.
  • Insoluble grit: Usually granite chips, flint chips, or course gravel that tend to stick around in the digestive tract for longer since they don’t dissolve.  Insoluble grit can be provided to birds as a supplement.  However, flocks that are free-ranging in a natural environment will also usually manage to eat enough small stones or pebbles.

For adult birds, granite chips are the most effective form of insoluble grit because they wear down very slowly in the gizzard. Oyster shells and crushed eggshells are not a replacement for insoluble grit because they are not strong enough to help with grinding. Do not use sand as grit for any birds since the particle size is too small.

You want to feed the largest size grit your flock will eat in normal amounts (~20g per bird per week).  Having the larger size will stop it just passing right through the digestive tract.  Feeding grit that is too small can lead to crop impactions.  If your birds are eating too much grit, switch to the next largest size particle.

There aren’t currently any commercial brands of insoluble grit specifically made for poultry in New Zealand so many people will use pea metal (small crushed rocks and rock chips used for construction and landscaping).

How Much Grit

You may not have to provide supplemental insoluble grit if your birds are only eating a commercial crumble or mash  since the food particles are already small enough to digest. However, if your birds are getting any other types of food like whole grains or vegetables as treats, they will need to have stones which they can probably find by foraging on free range.

Insoluble grit should be given free choice rather than sprinkled onto the diet since poultry will only eat as much grit as they need.  This allows each bird in your flock to choose the exact right amount for themselves.  The grit can be put in a separate container/feeder or sprinkled on the ground for them to find while foraging. Refill the insoluble grit as needed whenever it starts to get low.

Layers will eat about 75g to 150g of grit per month consuming more during winter when they are going through the moult process to build new feathers and during periods when they are producing a lot of eggs.  They will generally consume less grit during spring and summer.

Insoluble Grit for Chicks

Chicks should not be fed grit during the first week of life. If they are being fed on crumble, the particle size of the food is small enough that they won’t need any grit.  Once the chicks are weaned onto a regular diet, they will usually be able to find enough grit in their environment if they are free-ranging.