🦴 Calcium Metabolism: The Secret to Strong Shells & Healthy Bones

Why do some hens lay perfect eggs while others produce thin-shelled or shell-less eggs?

It’s all about calcium - and it’s more complex than you think!

🥚The Amazing Process:

A hen mobilizes 10% of her total body calcium DAILY to make ONE eggshell! That’s 2-2.5 grams of calcium per egg - a massive metabolic demand!

Where Calcium Goes:

🥚Eggshells (94% calcium carbonate!)

🦴Bones (skeletal structure)

💪Muscle function (contractions, including heart!)🩸Blood clotting

🕸️Nerve transmission

How Hens Get Calcium:

🍲Source #1: Diet

✔️ Layer feed contains 3.5-4% calcium

✔️ Free-choice oyster shell supplements (let hens self-regulate!)

✔️ Absorbed in small intestine

🦴Source #2: Bones

When dietary calcium isn’t enough, hens pull from a special bone calcium reserve called “medullary bone” - created specifically for eggshell formation!

Shell Formation Timeline:

⏰Takes 20-26 hours to form ONE egg

😴Most shell calcium deposited at NIGHT

❓Why? Hens aren’t eating at night but shell is still forming!

🌑They mobilize stored calcium during darkness

Signs of Calcium Problems:

❌ Many thin, soft, or missing shells

❌ Misshapen eggs

❌ Decreased laying

❌ Bone weakness/fractures

❌ “Cage layer fatigue” in high producers

Critical Management:

✓ Provide layer feed (16% protein, 3.5-4% calcium) to hen only flocks

✓ Offer free-choice oyster shell separately (hens know what they need!)

✓ NEVER feed layer feed to chicks (too much calcium damages kidneys!)

Your turn:

1. Do you offer free-choice oyster shell or just rely on layer feed? 🐚

2. Ever had a hen lay a rubber egg? What did you do?

2 comments

The Healthy Coop Collective

skool.com/thehealthycoopcollective

Vet-led community for backyard poultry keepers. Dr. Nisana, DVM, provides expert guidance on flock health, disease prevention, nutrition, & wellness.

Leaderboard (30-day)

+25

+18

🔥

+18

Hope O'Brien

Wendy Beatty