Natural calcium for poultry
BSF Organic supplies clean, graded oyster shell grit — a slow-release natural calcium source that keeps laying hens in lay and shells hard. Available in coarse, medium and fine grades, from a backyard bag to bulk by the tonne.
The difference it makes
A steady calcium supply means thicker, harder shells — fewer cracks, fewer losses, better birds at the nest box.
Calcium-deficient hens pull it from their own bones. Free-choice oyster shell protects skeletal health and keeps them laying.
Coarser grit works in the gizzard to help grind feed, so birds get more from every mouthful of pellets and forage.
Our grades
Same clean oyster shell — sized for the flock you keep. Not sure which? We'll help you choose when you enquire.
Largest pieces · ~4–8 mm
Chunky, slow-dissolving pieces that sit in the dish and in the gizzard. The longest-lasting calcium release and the best grinding action.
All-purpose · ~2–4 mm
Our most popular grade. A versatile size that suits the widest range of breeds and ages — the safe default for most backyard and small farm flocks.
Smallest pieces · ~1–2 mm
Small, easy-to-eat particles that can be offered free-choice or stirred through feed. Gentle enough for smaller birds and young stock.
Pack sizes
Every grade is available in each size below. Bulk and pallet orders are priced on enquiry.
A starter bag for a few backyard hens or to trial a grade.
The go-to bag for an established backyard flock.
Best value per kilo for smallholdings and bigger flocks.
For commercial farms, studs & produce stores. Delivered.
The science, simply
It's not just any calcium. The size and structure of oyster shell is what makes it work for a laying hen.
Larger oyster particles dissolve gradually overnight — exactly when a hen is building her shell — instead of flushing through like powder.
Offered free-choice, hens take only the calcium they need. No risk of over-dosing the whole flock through the feed.
Coarser pieces lodge in the gizzard and help grind feed, so birds get more nutrition from what they eat.
How to feed it
Put oyster shell in its own dish — don't mix it into the main feed. Hens that need calcium will help themselves; the rest won't over-eat it.
Check the dish regularly and refill so it's always available. A small amount goes a long way — most flocks get through it slowly.
Coarse or medium for full-size laying hens; fine for chicks, bantams, ducks and quail. When unsure, medium suits almost everyone.
About BSF Organic
BSF Organic supplies natural oyster shell grit for poultry keepers — from a handful of backyard hens to commercial laying sheds. Our shell is washed and graded into consistent coarse, medium and fine sizes, so you know exactly what you're putting in front of your birds.
We keep it simple: a genuinely natural product, graded properly, packed from small bags to bulk, and delivered without the markup of a middleman.