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.


  1. Hi – is it good enough that they get natural grit from the ground? – (my chickens are not kept in a run).

    • If the soil type is right and they have enough free range, then yes… But it is very cheap to buy mixed poultry grit and it lasts ages?

    • I don’t know the feed but some (BOC Farmyard layers for example) have grit in the pellets.

  2. I live near the sea and hundreds of razor shell clams get washed up every day. Would it be alright to crush these up and use as grit for my hens?

    • I don’t see why not. It is usually Oystershell they use but Razor shells I would guess have a similar composition.

  3. I have re-homed four ex-bats. I already had a Pekin cock and hen.
    Two of the ex-bats are laying very weak shelled eggs, sometimes too weak to survive being laid(come out broken or as a soft sac)
    They all have a large garden to range over, and I have oystershell and insoluable grit in a plant pot.

    Is there another reason for these soft shells?

    • Sadly, Ex-Batts can have very poor shell quality, especially as they age. They are at the end of the day ‘commercially spent’ and have given all they could over their 18 months in cages. The hens are not really ‘normal’ hens, they are a hybrid hen that has been created to do this with no concern with what happens after the first 18 months.

      Basically, consider a run of the mill pure breed that will lay 130 – maybe 150 eggs per year, these hens are producing 330 odd eggs per year on just enough food and water to do this. They don’t get time to rest.

      They normally won’t survive for as long as pure breeds either bless them.

      They might start laying good eggs again, sometimes they will lay soft eggs, it’s more common in high production strains.

  4. my chickens have got rid of nearly all the grass and its turned to mud expecially as the rain has come its all slushy is it ok for my chickens for when they r out the back

    • Mud is a haven for worms and bacteria. I would go for a covering of wood chippings that they can scratch through and can be changed periodically. See my page on chicken runs for more info.

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