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. Would it be beneficial to provide the hens with a couple of pieces of cuttle fish bone now and again, I ask because i use to breed budgies and found it essential for good egg production as a brilliant source of calcium. Brilliant site by the way thanks.

    • Possibly, it’s not something I have done before. Modern formulated layers feeds do contain the correct level of calcium for hens but I don’t see any harm in providing this.

    • It definitely would work! But oyster shell is likely cheaper. I’m in the States and here I can get a 50lb bag of oyster shell for a mere $14. The only difference between commercial feeds and what used to be fed is they’ve tried making it “conventient” with all the feed requirements mixed into one formula. I personally don’t like this method since I want to KNOW what is being fed to my birds. After the China-Canada dog food issue with the poisonous chemical that “faked” a higher protein result (but killed dogs), I would prefer to add my own KNOWN proteins and other minerals into my animals feeds. It used to be done and it can be still done. My parakeets and other caged birds don’t eat the unidentifiable commercial feeds, so why do our chickens? Its just something that bothers me. So I’ve been reading more on how to give them proteins and calcium and other needed items without depending on the secret recipes of Commercial feed companies. Even bone meal would work. My mom and aunts used to give it to their chickens when I was a kid. They also placed out the hides of the animals that were butchered, in front of the hen house in the late fall during butchering time, and allowed the hens to feast on all the fats and niblets of meat still on the hide. Extra Protein you know.

  2. Hi, found your website very useful well done. I’m new to keeping chixs, I understand how they use grit to grind food in their gizzard but should it be kept seperate or added to the layers feed and could I use sand.


    • Keep a separate tub of it. A flower pot burried in the ground with just a couple of inches sticking out with a peg through the holes at the bottom to hold it down works well. Flint grit is very cheap although some people use sand. I haven’t tried this.

      • Often sand can be too fine. Courser sand would work though. I find giving them a bit of variety to choose from seems to keep them happy too. I watch what the wild birds are generally choosing from the gravel patches and I often scoop up some of that for them to test as well.

        • I think you are right. I read recently that insoluble grit needs to be the correct size for the bird – so chick grit wouldn’t be very good for chickens and sand is generally about the size of chick grit.

  3. Hi,
    Brilliant site! I have been reading up as I am about to start keeping a few chickens and have found your site very useful Thanks!!
    I have been told the birds will do very well on just their shells crushed and baked. Is this correct? Also regarding the flower pot method you mention above, is this instead of buying a grit hopper?

    • They need insoluble / flint grit for digestion that they can often get from free ranging but Oystershell grit (for calcium) can indeed be replaced by crushed and backed egg shells as these are mainly made up of calcuium anyway. It’s worth noting that modern layers feeds contain sufficient calcium for most hens anyway but it’s usually good to have some extra available anyway. Hybrids that lay lots of eggs usually need extra calcium.

      Yes, the flower pot will do the same job as a grit hoppper. Grit can get wet, it doesn’t need to be kept dry like their feed…

  4. Thank you for all the useful information on your website. I am new to keeping chickens and after a bit of research got my first 2 yesterday, which I hope will soon become 4 if all goes well. There is a point that I’m not clear on. When I bought the chickens the poultry keeper told me that I would not need to buy extra grit as there was enough in the layers pellet feed I bought. Is this correct, or do they still need an extra seperate bowl of the flint grit you mention to help with digestion? Thank you.

    • Soluble grit (Oystershell) used mainly for egg shells, provides Calcium and modern day layers pellets usually contain a sufficient amount of calcium.
      Insoluble grit which is needed for digestion (to grind down food in the gizzard) needs to be picked up by hens that free range, or provided. Some (cheaper) pellets also contain insoluble grit (Farmgate Layers feeds are one, they come in a green plastic bag but check the ingredients). 20Kg of feed can obviously be cheaper if it has grit included due to the weight…

  5. This site is very good and i have learned a lot ,thank you,Do we put grit bought in pet store in the same feeder as the layers pellets, Elizabeth

    • No, use a separate container. I dig a hole, burry a plant pot almost all the way in the ground and peg it down through the holes in the bottom, then top up with grit. It can get wet and the water runs through.

  6. 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.

  7. 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.

  8. 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.

  9. 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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