Why do Chickens need
Grit and Oyster Shell?
Someone asked me the other day why chickens eat their own
eggs. My answer to this question is pretty simple, “Chickens are smart, if they
need something in their diet they are not getting, they will find it”. What
they need in their diet when they are eating their own eggs is, 1) calcium from the egg shell and 2) protein
from the egg. Which leads to the question of, supplementing with Oyster shells
and or Grit. And what is what?
So why do they need
grit? Chickens don’t have teeth so they use this (insoluble) grit to grind
down their food. If they are free ranged they can find it for themselves. If
they are in a coop most or all of their lives, you will need to provide them
with their needs. Layer Chicken feeds do provide both grit and oyster shells, and
the bag will tell you there is no need to supplement, that the food is fully digestible,
but is it enough? If you are only feeding food scraps, treats or scratch feed,
to chickens in a coop, yes, you need oyster shells and grit.
Chickens have this thing called a gizzard. You know what
that is, they fry or steam them at your local chicken place for a tasty chewy treat. In
a chicken, before food get to the gizzard there is this thing called, the
proventriculus, food is mixed with acids and digestive enzymes. Then on to the
gizzard where (insoluble) grit accumulates, which with a strong muscular
action, grinds the food down. So to digest their food correctly, chickens need
insoluble grit. It is cheap enough to buy so it’s easy to provide some, just to
make sure they are getting enough.
Grit- VS- Oyster
Shell
Oyster shell also called Soluble Grit (the most common
being Oyster shell grit) often gets confused with Insoluble grit. Insoluble
grit is usually made of granite or flint.
Don't confuse oyster shell with grit. Grit is insoluble. It stays in the gizzard and it's used to
grind food. Oyster shell dissolves in the
gut. Its job is not to do with digestion - it's to add calcium to the diet of
laying hens, for optimum health your chickens need both .
Soluble grit (oyster shell)
is digested by the hen and contains calcium, most of which is used to form
strong egg shells. The majority of an egg-shell is made up of calcium carbonate
and a constant supply of oyster shell grit ensures they have sufficient calcium
in their bodies. If sufficient calcium isn’t available, hens can lay soft or
poor quality shelled eggs.
As an alternative to oyster shell grit, baked crushed egg
shells can also be used since they are mainly calcium carbonate too. Hopefully
you will have a good supply of egg shells!
Do all chickens need
oyster shell?
No, absolutely not.
Chickens who aren't laying will get enough calcium from their normal
feed. Only hens who are laying eggs
need to be given additional calcium in their diet - when they're in active lay,
they use four times as much calcium as a non-laying hen. Giving additional
calcium to chickens who are not layers is detrimental to their health - it can
damage their kidneys and is potentially fatal.
Why do laying hens
need oyster shell?
Making egg shells takes a lot of calcium, and some laying
hens create one egg each day. That's a
lot of calcium.
If a hen doesn't have enough in her diet, her body will
steal calcium from her bones to create the egg shell. That leaves bones very brittle with the
potential for easy breakages - like osteoporosis in humans.
Lack of calcium in the diet can also lead to soft-shelled
eggs, which in turn can lead to egg-binding, a potentially fatal condition.
Although some commercial feeds contain calcium, it is not
enough to supplement the amount a laying hen uses. She therefore needs to be offered additional
calcium in her diet - and oyster shell is an excellent source.
When should a hen be
given additional calcium?
Most hens will start to lay when they're about 20 - 21 weeks
of age. Oyster shell needs to be given
from around 18 weeks - just before they're due to start laying.
Do not be tempted to give additional calcium supplements in
any form earlier than that - it is potentially damaging to a young chicken's
kidneys.
Hens who are not laying eggs, and roosters (cockerels) do
not need additional calcium. Don't worry about working out who needs what - as
long as you offer it freely (i.e. leave it available all the time) they will
instinctively know to take it as and when they need it.
Make it available to your flock year round. If hens aren't
laying as much in the winter, they will simply slow down on how much oyster
shell they take.
How should oyster
shell be given?
Different laying hens have different calcium needs. Not every hen, for example, lays an egg every
day.Young hens and all ages of male chickens (cockerels / roosters) do not need
additional calcium at all.
For that reason oyster shell should never be mixed in with
feed. Doing this risks damaging the
kidneys of those who do not require it.
It is suggested that you give oyster shell grit in a
separate container than their chicken feed. Using a hopper or gravity feeder
attached to a sheltered wall protected from wind and rain. If you’re on a
budget, or want to leave it outside, you can make a hopper out of a plastic
flower-pot. Bury half of it in the ground, make sure it has holes in the
bottom. Top it up with oyster shell grit. When it rains, it will be able to
drain freely through the holes
Chickens will instinctively take as much as they need; those
who don't need it will not touch it.
Insoluble Grit (flint or granite)
There are different grades of insoluble grit depending on the age of the
chicken. Baby chicks should have a very fine mix; as they get older it should
be more coarse.
At what age should
chicks be given grit?
If you're raising chicks in a brooder, i.e. without a broody
hen, do not feed treats (and grit) too early.
Chicks need to learn first what their 'proper' food is, because that's
where they will get the balanced nutrients they need.
I don't recommend giving
treats until they're at least two week old but that's personal
preference - with a broody hen they'll eat other foods from a couple of days
old and will pick up grit naturally as they peck.
Babies who are eating nothing but a commercially produced
starter feed do not need grit. The food is soft enough to be absorbed without
the need for grinding.
However, as soon as chicks are given any kind of treat food,
or grains such as scratch feed, they need some form of grit. It doesn't matter whether you think the
treats are soft and easily digested - any food other than chick starter
requires it.
Grit for babies up to three weeks can be something as simple
as bits of sandy soil still attached to a lettuce, or a clod of grass with
earth attached. If using sand it needs
to be a builder's or all purpose grade : play sand is too fine and won't aid
digestion. It will go in one end and
straight out the other.
Once they're over three weeks you need to look for a
'grower' grit which is coarser; they can use that from three weeks until around
two months, after which they will require an even coarser, adult mix.
When do adult
chickens need grit?
Adult chickens who are fed only commercial food and do not
have access to any other food or treats do not need grit. The feed is soft enough not to require
grinding.
However, just as with baby chicks, once your flock is eating
anything else including any form of treats, they need to be given something to
help them grind the food.
An adult chicken needs a fairly coarse mix so you need to
ask your feed store to make sure you're getting the right grade. If it's too fine, it will pass through the
system without stopping.
Any age of chicken eating anything other than commercial
chicken feed needs to have a source of grit freely available. Pecking dirt from
the ground may not be enough.
Any age of chickens eating anything other than commercial
feed need to have a source of grit.
How to feed Grit?
You can feed grit the same as you feed oyster shells in a
hopper or sprinkle it on the ground. Chickens are going to pick it up in their
daily pecking and scratching. In free ranging chickens they will scratch and
pick it up as they need it in nature. You may not want to mix it due to the
fact that some chickens may want or need one or the other. Remember they are
smart they will find what they need.
References
https://poultrykeeper.com/keeping-chickens-faq/why-do-chickens-need-grit-oystershell/
