Iron is the mineral at the heart of hemoglobin — the protein that carries oxygen from your hen's lungs to every cell in her body. A laying hen deposits about 1 mg of iron into every egg yolk, so daily demand is surprisingly high for a bird that weighs only 2 kilograms. Iron also builds myoglobin in muscles, which matters for active free-range hens covering serious ground through the day. Beyond oxygen transport, iron is involved in immune cell function and the enzymatic reactions that convert feed into usable energy.
Chickens absorb heme iron from animal sources (insects, worms, meat scraps) much more efficiently than non-heme iron from plant sources (leafy greens, grains). This is one of the reasons foraging flocks that scratch up bugs and earthworms tend to have better overall health markers than birds fed a strictly plant-based diet. Vitamin C from fresh greens enhances the absorption of non-heme iron, creating a natural synergy when hens eat a mixed diet of greens and grains.
An important interaction to be aware of: the high calcium content of layer diets (3.5 to 4%) actually suppresses iron absorption because calcium and iron compete for the same intestinal transport mechanisms. This means laying hens are at higher risk of marginal iron status than non-laying birds, making dietary variety and foraging access genuinely valuable for iron balance.
Laying hens need roughly 60 to 80 mg of iron per kilogram of feed. A bird eating quality layer feed with regular foraging access for insects, worms, and leafy greens is usually well covered. Dark leafy greens like spinach and kale provide plant-based iron. Free-range time is genuinely one of the best iron supplements — a hen scratching for insects gets the highly absorbable heme iron that nature intended.
0.01% of daily nutrient intake
Iron makes up 0.01% of your chicken's total daily nutritional requirements by weight. That's a tiny amount — but it matters.
Pale combs and wattles (the most visible early sign), lethargy, reduced egg production, pale egg yolks, weakness, poor appetite, slow feather regrowth after molting, increased vulnerability to parasites and infections
Iron overload from normal diet is uncommon, but excessive supplementation can interfere with zinc and copper absorption causing secondary deficiencies. Rusty water sources can contribute unwanted iron. Iron toxicity causes liver damage, dark or greenish droppings, and reduced feed intake. Keep waterers clean and free of corrosion.
| Life Stage | Size | Min | Max | Unit | Notes |
|---|---|---|---|---|---|
| Adult | — | 60 | 80 | mg/kg feed | High calcium in layer diets suppresses iron absorption. Foraging for insects provides highly bioavailable heme iron that compensates. |
Source: NRC Poultry 1994; Merck Veterinary Manual
Vitamin C dramatically enhances the absorption of non-heme iron (the form found in plant foods) by converting ferric iron (Fe3+) to the more absorbable ferrous form (Fe2+) in the chicken's gut. While chickens synthesize their own Vitamin C, the amounts may be insufficient during heat stress or illness, precisely when iron absorption efficiency matters most. Laying hens are particularly vulnerable to iron depletion because high calcium intake from layer feed already suppresses iron absorption.
What this means: Feed iron-rich treats like spinach or lentils alongside Vitamin C-rich foods like broccoli or peas to maximize iron uptake. This pairing is especially valuable for confined laying hens who cannot supplement iron through insect hunting and soil scratching like free-range birds do. During summer heat stress, vitamin C-rich greens serve double duty by boosting both antioxidant defense and iron absorption.
