[grinling]

I've been offered mussel shells; can I use that crushed up?

[Aunt Sally]

No they are much too hard.  Oyster shell is soft and can be digested and absorbed.

[Lindeggs]

Hmmm... interesting. 

When I was digging up the old compost area to put in my coop, I dug up a lot of old shells.  They were all chalky and brittle from being out in the elements for such a long time.  I have crushed them up and intend to use them as shell grit for my hens.

Presumably these old, weathered shells would be suitable as grit?  There is a mix of oyster, paua (similar to abalone), mussel, scallop and some I don't know the English word for (like pipi and tuatua).

[Aunt Sally]

If they are crumbly and weathered I would imagine they would be fine.

[Sassy]

I have not tried it but some people use egg shell that has been baked in the oven - to sterilise it

[hillfooter]

All chickens basically require grit to help grind their food up and often insoluable grit is used (granite or crushed gravel) for this though crushed oyster shell serves this purpose too as well as being a source of calcium.  Free range birds will usually find sufficient for this purpose from the ground.

Chickens also need calcium for egg production and if fed on a balanced compond feed young (pullets) will get this from their layers pellets but older hens may need additional supplements available ad libitum and crushed oyster shell is the best source.  Again chx free ranging on chalky soil will find plenty themselves if they need extra from their feed.

Most people provide grit ad lib anyway as I do even for chx on grass, even though it's arguable that only chx not kept on free range ground really need it. Here's three types usually sold in feed merchants.

Insoluable - crushed gravel basically, sometimes just called grit
Soluable - crushed oyster shell (contains about 90% calcium) which also will provide a grinding agent too.
Mixed - often has oystershell, other crushed shell (crushed mussel would be ok as an mostly insoluable grit) and gravel.  I use mixed usually and don't make it easily acessible I like to encourage my birds to be active and work for their living.  That way they stay free from boredom and mentally healthy.

Don't as some do routinely mix it in their feed unless you are short term treating for some gross deficiency and then limestone flour is a more absorbant form of calcium to use for this purpose.


HF