The practical basics for a good shell quality


Egg shell quality is a major parameter to consider in layer flock management. It has a direct effect on layer flocks longevity and the economical result. An appropriate management combined with high genetic potential allow Novogen flocks to ensure premium egg quality until end of laying cycle. Barring major incidents, such as a vitamin D deficiency for example, egg quality is easily maintained until mid of production. Then, flock fatigue, correlated to its aging, inevitably affects the quality of the shell. It is possible to mitigate this aging-related effect, provided good management has been implemented before measuring its effects! Prevention is always more cost-effective than the cure!

The practical steps for maintaining good shell quality until the end of the flock are as follows:

  • The pullet quality (weight & homogeneity)

It is recognised that a quality pullet subject to light stimulation, i.e. at standard weight and in a homogeneous flock, is a determining factor in achieving a good laying peak, high persistency, but also good shell quality! This starting point is to be observed in order to optimise the performance of your batch. The brooding period is therefore the best time to invest in the future!

  • Light stimulation timing

Once the pullets are ready by achieving targeted bodyweight and uniformity, it is possible to perform light stimulation. It should not take place at too low bodyweight, otherwise it will reduce the egg weight and also the quality of the shell at the end of the laying period. Effective stimulation involves increasing daylight length by at least 3 hours over a short period of 3 weeks.

  • Feeding in production

A young layer will easily mobilise calcium from her medullary bone to form her shell every day, mostly at night. However, this must be supported by providing enough carbonate. In general, the coarse/fine carbonate distribution is approximately 60/40 in brown hens and 50/50 in white for a calcium intake of around 4 g minimum / hen / day. The feed should be chiefly ingested in the afternoon and just before night-time to promote good nocturnal calcification.


Graph. : Egg calcification process in laying hens

In the event of extreme heat and when allowed by local regulation, lighting in the middle of the night, coupled with food distribution and access to water can be used to maintain the consumption levels. The shell quality of a hen with too low feed intake will deteriorate more quickly with age.

It is important not to wait for the quality of the shell deteriorate to act, because for some hens, it will be too late! Decreasing phosphorus often improves shell quality because it competes with calcium for absorption. It is possible to start gradually lowering it from 40 weeks. It also optimises feed costs! At the same time, add more calcium. With age, egg size naturally increase so there is more shell to be created. From 4 g per hen per day, this can be increased up to 4.5 g at the end of the laying period.

  • Addition of further calcium

Manual or automatic intake of additional calcium, 1 to 2 g / hen / day in the afternoon improves shell quality in older hens. Marine origin shells are a good source of coarse calcium provided this raw material has good sanitary levels!

  • Additives

End-of-laying additives intended for shell quality can compensate for shortages occurring during the flock. This solution is often more expensive than investing in “basic” nutrients such as calcium, so it has to be timed properly. It is a last resort curative solution.

Therefore, the good management of layer flock, as well as of their diet, makes it possible to limit the effects of age on laying performance. Investments in “basic” nutrients such as calcium, phosphorus and pullet feed can directly improve shell quality. It is also important to optimise feed consumption in relation to amount ingested and distribution times. Layer flock management and nutrition must work together to allow expression of the genetic potential and thus achieve the best performance.

Shell quality is a constant preoccupation in layers, which must be prepared from the youngest age. I too often see a certain negligence in the quality of the pullets, whatever the country, which unfortunately degrades the production performances. Investing in pullets allows you to start on a good basis, which is essential.

Antoine Le Calvé

Nutrition Specialist, NOVOGEN

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