Increasing egg size is a significant objective in poultry farming as it is the method of classification for sale. Which factors are related to size, and how can we increase it?

Egg size grading

Hen eggs must be graded for marketing and pricing. Considering the variety of sizes, they have been graded by weight in grams. For this reason, there is a classification that equates weight and size.

Table 1. Correlation between egg size and egg weight.

* Method of classification – Mobanette3 – Moba Group

Increasing egg size: genetics

For decades, poultry genetic industry has carried out optimal and excellent selection processes. Selection makes it possible to obtain the maximum number of advantages and reduce the disadvantages of a genetic line of animals. These accumulated improvements are known as hybrid vigor.

Therefore, genetic selection influences the improvement of egg size. Other beneficial traits that have been obtained are disease resistance, rapid growth, nutritional efficiency, and earlier puberty.

Among the variables that control the improvement of egg size, genetics plays a 40% role. The other 60% of variables are non-genetic, also called environmental factors.

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Nutrition is always a key factor

Nutrition is a component involved in boosting egg size. There are some specific nutrients which, when supplied correctly, help to produce larger eggs.

Amino acids: methionine and lysine

Methionine is one of the most studied amino acids that significantly contribute to egg size improvement. Combined with another amino acid, lysine, makes it possible to obtain larger or smaller eggs, as required by the producer. For this reason, providing these amino acids helps to increase egg size.

Energy and fat

The energy and fat in the feed must be correctly balanced by a professional, such as a zootechnician. If a feed has an excess of energy, it can result in a lower feed consumption by the hens and therefore a lower egg production. Sometimes it is better to increase the fat to provide the kcal needed by the hen, instead of increasing the energy to avoid this. This balance of energy content is beneficial for the improvement of egg size.

Linoleic acid

Studies have shown that an adequate proportion of linoleic acid has a positive effect on increasing egg size. This long-chain unsaturated fatty acid must be supplied in the right proportions for each stage of hen production.

Protein

Protein is an essential component of any animal diet and must be balanced correctly. It is important to remember that eggs are food with high protein levels. Therefore, the bird also needs a good amount of protein in its diet.

Age and weight of the hen

As the hen gets more weeks old, the eggs are getting bigger. When hens start their laying cycle, the eggs will be small at first and then medium size. As they get older, the eggs are getting bigger.

Another substantial factor in increasing egg size is the weight of the hen. Therefore, if the birds are fed with sufficient nutrients during the rearing stage, they will reach the laying stage in better condition. A recommendation is that birds reach and exceed standard bodyweight.

However, during the rearing stage, several organs continue to develop. During the first 6 to 8 weeks of life, birds should be fed with starter and growth concentrates. Once this stage is reached, the skeletal system will have completed its development, and the bird can continue to develop. At this point, at eight weeks of age, a development concentrate is given to aid in egg size improvement.

Nevertheless, basing these parameters on the age of the hens is not always accurate. It is better to consider only the standard bodyweight of the strain according to life stage. The important thing is to be within the average and even exceed it by 60-80g. This method has two advantages. First, it helps to avoid malnutrition or growth retardation. And, secondly, to prevent overweight. These factors must be considered to ensure an increasing of the egg size.

Effect of lighting

Lighting in poultry houses remains one of the most significant parameters assessed. The effect of light on poultry has been studied for years and it is known that affects their behavior and development. In other words, light affects the improvement of egg size in hens.

In general, there are two types of lighting. The first, called slow decrease, consists of supplying the birds with more hours of light. This results in the fact that the birds are having more hours available for feeding and nutrition. In the long-term, this benefits the producer as the birds gain more weight. Although the birds take longer to develop, there will be undoubtedly an improvement of egg size under the system of more daylight hours.

On the other hand, there is a fast decreasing type of lighting. In this system, there are fewer hours of light available each day for the birds. Therefore, the effect observed is that birds develop faster. However, under this method, the eggs are smaller in size. This system is most used in broiler poultry farming.

Table 2. Comparison of lighting types used in increasing egg size.

General bird health and intestinal health

The general health of the bird is a requirement to obtain an increase in egg size. The hen must remain free of stress, diseases, fear, injuries, among others. These pathological situations are detrimental to egg quality and the overall health of the hen. In order to achieve a good egg quality and size, it is essential to maintain the general health of the hen population.

Poultry farm health is related to vaccination and the prevention of infectious diseases. Some of these diseases directly affect egg quality and reduce egg size. It is advisable to create health and infectious disease prevention plans for hens.

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In addition, to achieve high egg quality and increased egg size it is necessary to maintain proper intestinal health. The condition of the intestinal mucosa is a parameter that goes hand in hand with general health and nutrition. The intestinal epithelium is responsible for the absorption of all nutrients supplied in the poultry diet, so it must always remain in good condition.

Adding intestinal conditioner pronutrients in the diets can help to improve egg quality. These molecules of natural origin promote the condition of the intestinal epithelium by favoring its regeneration and functioning. This is reflected in an improvement of intestinal health, general health, and egg quality.

Conclusions

Increasing egg size is a constant goal in poultry farming. Egg size classification is an established international requirement. Considering production systems, and economic aspects, it is possible to play with the factors involved in egg size. The most important factors affecting the improvement of hen egg size are five. The first and second are genetics and nutrition. Third is the weight and age of the hen. Fourth is lighting. Finally, intestinal health should be considered as an important factor affecting hen egg size.