There are two types of poultry grit available. Flint grit or insoluble grit which is used for grinding down food and Oystershell grit, a source of calcium to help form strong egg shells.

Flint or insoluble grit

Chickens don’t have teeth, apparently, they are very rare, so to grind down their food, they use a strong muscular organ called a gizzard. flint grit for chickensChickens pick up grit whilst foraging, which is kept for a while in the gizzard to perform this grinding process. If your chickens are kept truly free range then they will find enough of this on their own but these days, few of us have the space or the security from predators to be able to allow them to do this naturally.

Flint (or insoluble) grit is cheap and available from most good pet or farm shops, the container you put it in costs a little more though if it is going to last.

Oystershell or soluble grit

oystershell grit for chickensIn order to form strong egg shells, chickens require a certain amount of calcium in their diet. Most of an egg shell is made up of calcium. These days, with the research that has been done for formulated feeds (available as layers mash or layers pellets), it isn’t so critical to provide oystershell grit because layers feeds contain sufficient calcium, however, it’s cheap and it’s easy to mix some in with the flint grit that they need above so it’s a good idea to provide some, in case they need more calcium.

High production hybrid hens are capable of producing a staggering number of eggs in a year on very little feed (known commercially as the ‘conversion ratio’) so they are more likely to need the extra calcium to be able to produce the right number of eggs of sufficient quality.

If you can’t find Oystershell grit from your local store, baked, crushed egg shells will do the same job – after all, they are mainly made up of calcium! Put them in the oven for 10 minutes to dry them out and crunch them up before mixing  them in to your grit hopper.

Although grit is heavy, if all else fails, you can still buy it online here. A small bag lasts for a long time.

Grit hoppers

Grit containers come in a variety of shapes and sizes – the priority is really to make sure it doesn’t get tipped over or filled up with water. There are some good galvanised grit hoppers like this one that will last a lifetime but will cost you a few pounds more to start with.


    • You really need a diagram. This site is for beginners so doesn’t really cover this.

      Try searching on for this as there is some information there. Remember only to clip one wing and not when feathers are growing and full of blood.

  1. Great site love your work.
    Now ‘oyster shell grit’ can I use crushed scallop shells instead (which is high in calcium) or any other double shelled sea critter. If not what is in the oyster shell that makes it so important?

    • No it can be any crushed shell that is high in calcium – it is just oyster shell is what is normally available. I have had some with crushed cockle shells in it.

  2. I have a box of old sea shells (probably over 10 years old) that have been sitting in a dusty shed. Can i use these to make my own shell grit?

  3. i have six warren hens they are about 18 months old and have been laying well for the last 12 months, they have full range of my garden for most of the day and are locked away at night .I feed them on layers pellets in the morning and mixed corn, scraps ,rice etc in the afternoon they always have a good supply of clean water and plenty of oyster shell available to them .I also feed back dried eggshells to them.but just lately i have have some very soft egg shelled eggs these seem to be laid at night as they are under the perch first thing in the morning they usually lay in the nest box during the day .All my chicks look healthy and i think they are happy and have everything they need i add supplement to there water(acv) on occasion.Why do you think i am getting soft eggs?

    • Soft eggs can come and go with the start or end of lay, they are more likely in hens that lay a lot of eggs such as Warrens and are more likely to occur as the hen ages. I would see how they go over the next few months, other than additional calcium through greens and soluble grit (or egg shell as you are feeding) I don’t know what else to suggest.

      There are conditions I have read about that cause the malabsorption of the calcium by the hen, in other words she can’t use the calcium you are giving to her but its not something I know much about.

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