Calcium is an essential element to maintain the skeleton and obtain qualified eggshells in layers (Martín 2019; Technonews 2015). For these reasons, hens have high calcium requirements that need to be met, as much as possible, through the calcium present in the diet.

Including the right amount of calcium in the diet will help to minimize the percentage of broken eggs and bone problems, which, consequently, will result in good performance rates and high-quality eggs.

Evolution of calcium requirements

Diets for pullets and laying hens should meet the requirements of each development stage. This means that the calcium inclusion in the feed needs to be adjusted to the feed intake and the current needs of the pullets and hens.

Table 1. Calcium requirements (%) in layers. Adapted from Rostagno, 2017
Age (week)1-45-1011-1516-18Average
Calcium (%)0.9700.9500.8602.2004.508

Calcium requirements are the highest during the laying period, especially right before and during the laying peak (Saunders-Blades et al. 2009). These requirements start increasing during the pre-laying period, when they are around 2.2%, and reach 3.8% at the start of egg production. As the laying period goes on, the recommended calcium levels increase above 4%.

Content of calcium in different sources

The content and purity of calcium sources must be considered during feed formulation to adjust the levels of this mineral to the birds’ requirements. The content and purity of the ingredients will have an impact on the final percentage of calcium available in the digestive tract, the one to be absorbed by the animal.

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Sources: (Blas et al. 2019; Rostagno et al. 2017)

Particle size

Particle size of the calcium source needs to be considered, too, since it is related to the gut retention time.

Longer gut retention periods in the digestive tract increase calcium utilization. Besides, since it extends the duration of calcium absorption, it is possible to supply calcium when the animal is no longer eating, which is at night, and this concurs with the period of eggshell calcification (Saunders-Blades et al. 2009; de Witt et al. 2009).

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This chart shows how coarse calcium sources (between 2 and 4 mm) increase with layers’ age, because their digestive tract is more adapted to bigger particles and hens would prefer big particles as they get older.

How can we help you?

In Global Vet’s Lab, we offer the feed formulation and analysis service to evaluate and optimize the dietary levels of calcium to optimize productive performance and prevent the problems caused by calcium deficiencies.

To use the service, please contact us through our webpage or email at


Blas, C. de, P. Carcía-Rebollar, M. Gorrachategui, and G.G. Mateos. 2019. Tablas FEDNA de composición y valor nutritivo de alimentos para la fabricación de piensos compuestos FEDNA (Fundación Española Para El Desarrollo de La Nutrición Animal). 4th ed. Madrid.

Martín, Nuria. 2019. “Formación de La Cáscara de Huevo.” Veterinaria digital. Artículos.

Rostagno, Horacio Santiago et al. 2017. Tablas Brasileñas Para Aves y Cerdos. Composición de Alimentos y Requerimientos Nutricionales. 4th ed. ed. Horacio Santiago Rostagno. Universidad Federal de Viçosa, Departamento de Zootecnia.

Saunders-Blades, J. L., J. L. Macisaac, D. R. Korver, and D. M. Anderson. 2009. “The Effect of Calcium Source and Particle Size on the Production Performance and Bone Quality of Laying Hens.” Poultry Science 88(2): 338–53.

Technonews. 2015. “Los Requerimientos de Calcio y Fósforo En Gallinas Ponedoras.” Veterinaria Digital.

de Witt, F. H., N. P. Kuleile, H. J. van der Merwe, and M. D. Fair. 2009. “Effect of Limestone Particle Size on Bone Quality Characteristics of Hens at End-of-Lay.” South African Journal of Animal Sciences 39(SUPPL. 1): 41–44.

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