Although in a breeder flock both sexes are responsible for good fertility, raising and keeping good quality males during rear and throughout the stage of production is particularly important. A well developed body is the basis for keeping fertility at a high level over a long period of time.


By Jorge Amado
Head of Technical Services for Aviagen in Central America, Mexico and the Caribbean


The key to promoting and developing a good strong skeletal frame size for males is to provide the correct environmental conditions and encourage good feeding and drinking behavior during the brooding period.







– Air temperature 30°C (86.0°F), measured at chick height in the area where feed and water are positioned

Litter temperature 28-30°C (82.4-86.0°F)

Relative humidity 60-70%

Light intensity 80-100 lux (7.4-9.3 fc)

Feed on paper covering 100% of the rearing space

Twelve feed trays per 1000 chicks

Eight bell drinkers and 12 mini drinkers per 1000 chicks

Eight to 12 birds per nipple drinker

If possible, an initial visual grading of the males should be done around 7-10 days of age with chicks graded into three or four subgroups according to body size and weight. This will help promote a good start and provide chicks with an equal access to feed and water.



By four weeks of age, the average weight of males should reach approximately 755 g, ranging up to 800 g.

At 28-29 days of age (when 50% of the skeleton has developed) a full evaluation of the flock should be made.

Birds are graded and separated into different weight categories (light, average, and heavy). In this way each group is raised separately to achieve the final body weight and desired uniformity.

Poor quality males should be removed and a male reduction program implemented, which removes very light males or those with physical defects.

To further improve the uniformity of the males, it is advisable to make up to four selections during the rearing period.

That is, at 4, 10, 15 and 20 weeks of age, removing males with a poor physical condition and relocating the males within the groups according to their weight.

In this way we can ensure the maximum possible uniformity in each flock. The objective is to finish the rearing period with an 11% male to female ratio.



Careful daily management, maintaining adequate feeder space by gradually increasing the floor space (flooring space after 10 weeks of age should be 3 to 4 males per square meter), being present during feeding time to check for uniformity and speed of feed distribution (ideally <3 minutes), are powerful tools for rearing good quality males.

During the production phase it is essential to maintain the correct track length at all times so that uniform and timely feed distribution is maintained.

To achieve this the track length should be reduced or feeder pans closed off as the male population declines.

However, the amount of feed per male should be increased throughout the production period in small portions of 1-2 g per bird every 2-3 weeks.



Male body weight, breast condition and muscle tone should be carefully monitored on a weekly basis and any adjustment to feed allocation should consider both body condition and body weight.

Too often, farm managers only focus on the average body weight of the males in each house and overlook the importance of monitoring the uniformity of the males. Poor uniformity can negatively impact fertility later in the production cycle if left unchecked.

Body weight records alone will not provide an accurate measurement of body condition. As seen in Figure 2, even within the average body weight there will be underweight (Male 1) and overweight males (Male 3).



Fleshing of males should be monitored weekly using a system in which:

A score of 1 indicates that a male is under-fleshed with poor muscle tone

A score of 3 indicates that a male is correctly fleshed

A score of 5 indicates that a male is over-fleshed with firm muscle tone


An excessive proportion of males above and below average indicates a lack of management in regards to feeding. Efforts should be made to ensure that all males have access to the feeders and that feed is distributed quickly and evenly.

At the same time, it is necessary to remove the lighter males from the flock.

It is also important to remember that body development of the male changes with age (Figure 3).




Another useful measure to maintain and promote the quality of the males is the use of a so-called “male restaurant” during the production period.

These restaurants are a way of feeding the males separately from the females. Feeders can be placed at the side of the houses, using nets or curtains, to keep the males separate from the females for one to two hours during feeding.

This system ensures optimal feed intake for the males and females by allowing:

Optimum nutrient intake for both males and females,

The males to finish eating without any distractions,

The females to eat without males stealing feed and

The male feeders to be positioned at lower heights so males of different sizes can eat more comfortably.

Once trained in this system, males will instinctively go to the feeders within the “restaurant”. It is important to ensure that all males have access to feed simultaneously in these restaurants.



The rotation of males is not necessary if good management practices have been implemented. However, it can be useful to improve persistency in fertility and maintain hatchability with low biosecurity risks since all males are from the same flock.

With this system, approximately 30-40% of the males will be exchanged between pens or sheds of the same flock.

This rotation of males helps to re-establish social order within each population, thus enhancing mating behaviour.

The first rotation of males should take place when fertility is at its peak (approximately 35 weeks of age), and should be repeated every 5 to 10 weeks throughout the production cycle.

With a detailed management in rear, production flocks will not need to add young males to older flocks, allowing for an improved biosecurity status on the farm.

Young males should only be added to the flock if the rate of males to females falls below 7.0-7.5%.





Good male management requires adequate attention to detail to achieve the best possible results.

This can be accomplished by:

  • Maintaining a correct growth profile from the moment they are placed as day-old chicks.
  • Implementing a good selection program during rear with the goal of retaining only the best males.
  • Always ensuring a high level of uniformity that will be achieved by:
  • Adjusting the feeder space for age
  • Maintaining the good feed distribution at all times
  • Promoting uniform feed intake

It is essential to frequently monitor and react to changes in body weight and body condition during production. If needed, take corrective measures.

Once the males have begun to decline in physical condition, it is difficult to regain the original condition and mating activity, as well as fertility.

Management practices such as male restaurants or rotation of males can be useful tools to help maintain a high level of mating activity, thus ensuring high fertility and hatchability.

Finally, it is of paramount importance for producers to monitor the behaviour of males and females, in order to achieve and maintain the highest possible level of fertile hatching eggs.






Magazine aviNews aviNews International December 2021



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