The starter phase in broiler farming is a key stage in the production cycle. The length of this period varies depending on the management system, but, generally, it considers approximately the first 14 days of the birds’ life. In this phase, chicks’ organs and immune system must develop properly in order to achieve the performance objectives in later phases. Also, in this phase, certain stressful situations occur, such as the reception on the farm and some vaccinations. Therefore, at this stage, broilers management becomes a crucial factor.

1. Getting ready for a new production cycle

Once the previous fattening cycle has finished, it is necessary to adapt the facilities for the next production cycle. Everything must be in optimal conditions in order to avoid problems in the new fattening cycle. At this point, the following should be considered important for broiler management:

• Emptying, cleaning and disinfection of the shed, as well as feeders and water troughs, and all equipment. A depopulation of several days between two production cycles is recommended.
• System repairment. The lighting, ventilation and heating systems, among others must be perfect conditions.
• Cleaning the silos where the feed will be stored for the next cycle, as well as the water tanks and pipes, to avoid infections through this origin.
  • Proper placement of the new litter (qualitatively and quantitatively).
  • Start-up and testing of the equipment 24 hours before arrival and ensure that the litter has the appropriate temperature at the chick reception (34°C).

2. The reception of the chicks

From the time the chicks hatch and until they are received in the fattening farm, it can take between 24 and 36 hours and, during this time, they feed on the remaining yolk. During this period, transport from the incubator to the farm also takes place, which is a stressful factor. Therefore, it is essential to receive the chicks as quickly and carefully as possible. On one hand, to minimize initial stress and mortality and, on the other hand, so that they begin to be fed as soon as possible, since the success on the production will depend on it.

It is necessary to check different aspects during the reception in order to guarantee a proper broiler management:

• Control of environmental factors: temperature and lighting

Once the chicks are received on the farm where the production cycle will take place, it is essential to maintain optimal environmental conditions that favour the initial development of the chicks. Regarding temperature, it should be kept in a range between 33°C and 35°C, depending on the age of the breeder and the average weight of the chicks at reception. 33°C is ideal for chicks of higher size or coming from the older breeders, and 35°C for the opposite case.

The lighting in the reception will be 24 hours uninterrupted, characterized by homogeneous intensity and distribution.

• Control of the chicks’ weights

It is very important to check the initial weight of the chicks, which should be between 40 and 42 grams, and the minimum acceptable is 36 grams. According to statistic studies carried out in recent years, one gram less of initial weight could be equivalent to 50 grams less of final meat.

At the same time, it is necessary to control the weight of the yolks through the necropsy of a representative number of chicks. The normal weight should be between 6-8% of the total body weight. If there is a significant percentage of the chicks with a yolk relative weight higher than these values, it means that the yolk has some vertical infection that comes from the breeders. It will also be an indicator of poor microbiological quality of the chicks. In this case, it would be necessary to administer a microbicide in drinking water during the first week of life, which helps to eliminate yolk infection and facilitates its reabsorption. Thus, the chicks will gain weight as normally as possible during the first week.

• Distribution of the birds in the shed

It is important to maintain an homogeneous distribution of the birds in the shed and to avoid crowds and competition for specific areas. For this, lighting, temperature and humidity conditions must be the same across all the farm areas.

Feeders and water troughs will contribute to the uniformity in the distribution of birds, so they should be homogeneously placed.

The number of feeders and water troughs must be proportional to the density of birds to avoid competition and crowds around them.

• The beginning of the feeding

Be sure that chicks have easy and immediate access to both feed and water is essential, because a disruption in the water supply would affect the feed intake and vice versa. Therefore, continuity in supplies must always be guaranteed, and feeders and water troughs must contain feed and water from a few hours before the reception.

In the first week of life, the chicks should multiply their weight approximately four and a half times. To achieve this, it is essential that birds begin to eat quickly. In addition to this, an early beginning of the feed intake has a positive effect on the reabsorption of the yolk.

Feed intake is favoured by high quality feed with adequate physicochemical characteristics. In addition, during the first days of life, intake is also favoured by certain physical activity. This can be forcibly stimulated by the farm staff, promoting that the chicks move, but always carefully.

To verify the correct feeding at the reception, it must be checked that, after 24 hours, more than 90% of the chicks have their crop full of feed. This is very important point in the broiler management.

3. Feeding in the starter phase

The first days of the starter phase are a learning period for feed and water consumption. Furthermore, an early and appropriate feeding is essential so that their digestive system develops quickly and completely and to develop better immunity. In the case of water, an early intake will initially help to counteract the consequences of the dehydration that the birds may have suffered before they arrived to the farm, and, later, it will increase the digestibility of the feed.

For a few years now, producers worldwide have agreed on the fact that the weight on the seventh day is crucial, since there is a correlation with the weight at slaughter. In this sense, one gram less of weight on the seventh day will be equivalent to 7 grams less at the end of the sixth week. Therefore, it is essential to routinely control the weight to ensure that the production objectives are met and to be able to early correct any deviation.

In the starter phase, protein levels are the highest, and metabolizable energy levels are the lowest throughout the cycle. This is because birds, at the beginning of the cycle, need higher protein levels that help the development of their muscular structure, while, at the end of the cycle, the energy must be higher for a quick fattening.

The starter phase can be divided into pre-starter and starter phase, but it will depend on the management system. If two phases are used, the protein levels will be higher in the pre-starter phase and decrease progressively in the starter phase, and the opposite with energy levels.

In addition to the nutritional profile, the formula must incorporate mechanisms that help in the prevention of the main poultry diseases, such as coccidiosis, imbalances of the intestinal flora or mycotoxicosis, among others. For this, the use of natural molecules such as intestinal optimizer and intestinal conditioner pronutrients is recommended. In the case of the optimizer ones, they strengthen the local immunity of the intestine, so that protozoal diseases, such as coccidiosis, are prevented. On the other hand, intestinal conditioner pronutrients increase the regeneration rate of the intestinal mucosa and improve the defensive barrier function of the gut, preventing microorganisms from penetrating, but favouring the absorption of nutrients.

Different strategies have been described for the mycotoxicosis control, but it has been shown that the addition of Silicoglycidol is highly effective, since this molecule binds any type of mycotoxins, preventing them from causing damage as they pass through the organism.

Keep in mind that the quality of the feed is essential, both from an organoleptic and a nutritional point of view. Feed quality considerably influences the intake and, to maintain it, the addition of preservatives to prevent feed spoilage is recommended. In this sense, those based on the cimenol ring, which is a natural microbicidal molecule, have been proven to be effective, since they eliminate pathogens from feed to not only its deterioration, but also possible digestive pathologies whose origin is the feed.

4. Environmental factors in the starter phase

Just like during the chicks’ reception, for a proper broiler management, the following factors must be controlled throughout the starter phase:

• Temperature

Temperature should be controlled throughout the cycle, but, in the starter phase, this is especially important because it affects feed intake. In this initial phase, a disruption of the feed intake has negative consequences on performance, which will be observed at the end of the production cycle. It is necessary to keep temperature within the comfort limits of the animal. If it is above the tolerance limit, animals will stop feeding to avoid heat overproduction. If it goes below the tolerance limit, birds will eat more, but energy will not go to fattening, it will go to heat production. Both cases lead to worse productive performance.

• Lighting

This is also a very important factor that must be controlled. Commonly, during the first day, birds are provided with light continuously. This way, the cycle starts with 24-hour photoperiods of continuous light, which stimulates feed and water intake and, consequently, guarantees a good start along with a good development of the digestive and immune systems. On the second day and progressively, one hour of darkness is added daily, so that birds get used to the dark phase of the photoperiod.

Between days 5 and 7, when chicks quadruple the birth weight, the hours of darkness are increased up to 6 hours and progressively increase throughout the starter phase, although this can depend on the management system. This increase ends approximately in the third week, when light hours are gradually increased again in order to promote growth in the final stages.

• Ventilation

An adequate ventilation must be maintained in order to control polluting or irritating gases, as well as humidity, oxygen supply, and to reduce the temperature when necessary. Irritant gases can lead to stress and immunosuppression and birds are especially susceptible to these conditions in the starter phase, because organs and immunity are still developing. In addition to this, predisposition to certain diseases can be increased, especially to respiratory disorders.

In the case of relative humidity, it should decrease as the days progress. As the density of birds increases, it is necessary to reduce the humidity to avoid the transmission of respiratory diseases, as well as to avoid deterioration of the litter and footpad lesions.

5. Prevention of diseases

During the starter phase, broilers are susceptible to many pathologies, some of which can be prevented with the inclusion in feed of the additives already described in “feeding in the starter phase” section.

For other pathologies, generally the viral ones, vaccination is commonly used. Usually, at the end of the starter phase, birds are vaccinated against Gumboro. When the birds are not vaccinated at birth, they receive Newcastle disease and infectious bronchitis vaccinations in the starter phase. It is recommended to add immunostimulant pronutrients a few days before and after vaccinations to increase the antibody titer and, consequently, the percentage of animals protected against these diseases.

Depending on the region and prevalence, vaccination against laryngotracheitis or adenovirus should also be considered.

6. Conclusions

The starter phase in broiler farming is a key stage to obtain good performance results at the end of the production cycle. In this period, there are critical points, such as the reception of the chicks or the stimulation of a correct and early feed and water intake. Routine broiler management and controls will be essential to ensure the proper progression of this phase, as well as to apply quick corrections to avoid deviations in performance.

In the initiation phase, all factors are equally important and must be controlled to ensure a proper progress in this phase. In this way, a successful starter phase will be completed, which is necessary for the subsequent grower and finisher stages.