Key factors in hatchability from fertile eggs are eggshell and egg quality (structure and cleanliness), egg disinfection, and egg handling and storage, incubation conditions (temperature, turning, humidity, ventilation), and, of course, disease. In fertility, the key factors are male nutrition and management. Males may be fertile, but they need to be able to mate with the female. Male overweight, size, or even female feathering issues may decrease mating success.

Executive Manager and Global Poultry Technology Lead
Novus
Hatchability has become a major concern for the broiler breeder industry in the United States. Presenting on this decline in hatchability at TECHTalks at the International Production and Processing Expo (IPPE) 2024, Novus’ executive manager and global poultry technology lead, Dr. Hugo Romero points out that similar problems have been reported from other regions. In his presentation, Romero examined the potential causes of this phenomenon and how adjustments to the ration can help combat it, and also evaluated the effects of amino acids and trace minerals on breeder fertility and chick development.
Based on his presentation at TECHTalks, we asked Dr. Hugo Romero about the details of the decline in breeding hatchability and methods of combating it. Romero shares the details for our readers.
Dr. Romero, what do hatchability and fertility mean? What is the difference between the two and why are these important in poultry production?
Let’s first consider some concepts. We have absolute values like number of eggs, number of settable eggs, and number of chicks hatched per housed hen. We also have percentage values like egg production, hatching eggs, and hatchability. Hatchability refers to the percentage of chickens hatched from the total eggs that we set in an incubator, which enables us to evaluate the hatchery’s performance.
However, when one analyzes the unhatched eggs and sees that some of them are unfertile, one should correct for them; this new corrected value is the hatchability from fertile. Sometimes we do not make it clear, and we could have the flock’s fertility as a confounding factor in the term hatchability.
Now, fertility refers to the percentage of eggs that are fertilized. We know that all hatched chicks and embryo mortality were from fertile eggs. The critical part is when the embryo dies at a very early stage and we could wrongly confuse a very early dead embryo with an infertile egg.
We tend to blame the fertility issues on the males -assuming that egg production is the main female indicator. However, this is not always the case.
Why has hatchability become a concern for the broiler breeding industry?What is the difference between the highest hatchability that can be achieved in theory and the results achieved in practice?
Hatchability in practical terms represents the final number of chicks that we have available to grow out and therefore affects all integration performance. However, we need to look at the egg production, fertility, and hatchability from fertile to see where the problem is: at the farm (female and/or male birds) or at the hatchery (disinfection, egg storage, ventilation, temperature etc).
What are the most important potential factors affecting hatchability and fertility? For example, can nutrition, stress and welfare be considered as important factors?
Key factors in hatchability from fertile eggs are eggshell and egg quality (structure and cleanliness), egg disinfection, and egg handling and storage, incubation conditions (temperature, turning, humidity, ventilation), and, of course, disease. In fertility, the key factors are male nutrition and management. Males may be fertile, but they need to be able to mate with the female. Male overweight, size, or even female feathering issues may decrease mating success.
However, we need to keep in mind that the first factor affecting the total number of hatch chicks is the total number of eggs per housed hen.
How can hatchability be improved? Is it possible to improve hatchability positively with adjustments in the ration (diet), or to what extent can it be improved?
Although for hatchability we want to focus on the hatchery performance we need to first focus on the breeder flock (management and nutrition).

To increase the number of chicks hatched good egg production is crucial. Secondly, good eggshell quality is critical. After all, a broken egg cannot be placed in the setter. Then, flock management is necessary to avoid floor eggs, and improve mating behaviour. This is also where male reproductive performance comes into play. We have seen some data suggesting the use of vitamins to improve performance. However, the results are confounded with breeder hen and male feed allocation. While we observed significant effects in old breeders, the effects were not significant at early or mid-age. Similarly, the effects were only significant in eggs in long-term storage (14 days).
Research has also shown that trace minerals can make a difference in egg quality and breeder performance. We saw improved egg production (3.6%) compared to inorganic sources and even 1.4% compared to other organic mineral sources.
Also in a commercial trial, we observed higher hatchability (as seen with the MINTREX® Trace Mineral Reduce and Replace™ strategy). Therefore, with more eggs and better hatchability, we increased the number of chicks per housed hen.
What should be considered in the diet of breeder flocks in terms of the quality of hatching eggs and the quality of roosters’ semen?
Dr. Edgar Oviedo at North Carolina State University and I deeply described broiler male management and nutrition in our chapter from NOVUS’ book, Breeder Management and Nutrition: Moving the industry forward. In the chapter we explain the importance photoperiod, diet and vitamin and trace mineral nutrition play in the performance of males. We also know males require lower crude protein and amino acids than females, but we still observe that, due to logistics on the farm, not everybody utilizes male-specific diets.
Could you also tell us a little about the effect of amino acids and trace elements on breeder fertility and chick development?
Amino acids have a direct effect on egg quality, feathering and male fertility. In nutrition, we typically set the lysine recommendation and then work with amino acid ratios with lysine. For example, excessive lysine and leucine might have some detrimental effects due to changes in reproductive tract pH. NRC (1994) and some researchers recommend high leucine/lysine (Ile/Lys) ratios compared with data from Europe; this might have an effect on fertility. Recent data shows that lowering lysine but increasing amino acid/lysine rations might increase feathering issues that we know could decrease female mating receptivity.
Where trace minerals are concerned, research shows certain highly bioavailable organic trace minerals (MINTREX® Bis-Chelated Trace Minerals) are shown to increase egg production, fertility and hatchability, ultimately increasing the number of chicks per housed hen.
Finally, is there anything else you would like to draw attention to?
It is very interesting that not all regions report the same extent of the problems with hatchability as reported in the U.S. Although some data is corrected by hen age, some data for total chicks per housed hen might not be adjusted at the same age. Additionally, we need fertility data and egg production to have a better description of the current situation. With better, more descriptive data we may be able to determine the root of the problem.