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- Environmental control in a poultry farm allows you to guarantee the productive performance of your flocks.
When we think of broilers in a controlled environment, we must assess two ages:
- The first week of the chick’s life.
- The last week before depopulation.
Current bird lineages are a product of the work of genetic companies and they increasingly require more restricted temperature ranges for optimal development. This invites us to see the controlled environment as a complement to the efforts of genetic companies.
This gain in size also implies other requirements such as maintaining the temperature, humidity and other factors within very narrow ranges to achieve maximum performance.
Figure 1. Evolution of lung size with the years. Notice how the size of the lungs has evolved with genetic advances. Before it represented 0.9% of the bird while in the current lines it represents only 0.6%.
To take advantage of all the genetic potential, we must keep the temperature as close to the average temperature (target) as shown in Figure 2, where we present a guide that relates the environmental control programs to be used based on the age of the chicken, as well as taking into account the temperature of the outer environment.
It is important to develop different environmental control programs for different ages and climates, since the environmental needs of the animals change. In addition, companies must standardize computer programs inside houses, in order to avoid interference that leads to handling problems.
Figure 2. Chicken age programs and outdoor environment for Ross 308 chickens.
- Chicks are 1-10 days of age.
- In “Program 1” we are going to focus on reaching the ideal temperatures via brooders and minimal ventilation and ventilation power.
- During this age, we use the air movers so as not to generate wind above the chicks.
- The air movers will work with the first and second static pressure.
- The first static pressure must be calibrated to offer between 5.5-6 m / s. The second static pressure should offer about 3.5-4 m / s, being able to use tunnel ventilation as an aid.
- This allows us to open the tunnel when they are using the second static pressure and thus refresh the air. At this age we can easily cool the chicken’s environment, being more careful since we do less damage to the chicken with heat than with cold.
PROGRAM 2: Growing
- Pullets are 11-28 days of age.
- In “Program 2” we will focus on reaching the ideal temperature through the combined functions of minimum ventilation, ventilation power and tunnel ventilation.
- During this period, when we use the air movers we are using the second static pressure most of the time.
- In addition, as the chickens are larger, we can use natural ventilation and tunnel when necessary.
- In this program we will use two extractors for minimum ventilation, the difference between the fan starts at 0.6ºC. We can even use evaporative panels for cooling, but in a very gradual, non-aggressive way.
- Also, we can use the panels when we have between 90-100% of the extractors on. This will help us lower the ambient temperature without having to use air velocity as a tool.
- Chickens are 28 days old until depopulation day.
- In “Program 3”, our goal will be to lower temperatures to keep the bird under maximum comfort and not stop eating.
- Normally, we will not use the power of ventilation (a little at night in some places) and we work with tunnel ventilation all night.
- In this program, the difference between the extractor starts at 0.4ºC.
- In addition, we can use evaporative panels more aggressively to lower the temperature of the house.
- Also, when we reach 90 to 100% of the extractors on we can also use the panels.
- Also in the last week, we used the so-called “bird cooling at night” method to improve conversions. We do that by setting the extractors with a clock or lowering the ideal temperature.
Comparing environments
Figure 3. Evolution of the temperature in a commercial layer house without a controlled environment.
In a test carried out in a cage for commercial layers, we see the temperature changes throughout the day (24 hours) in a shed without a controlled environment. Only for a very short period of the day the desired temperature was reached. In the 24-hour days there were only 8 hours when I found myself inside the neutral zone.
In Figure 4, in a controlled environment shed, we observe how the outside temperature fluctuates while the internal temperature remains within the desired range that the bird needs.
Figure 4. Comparison of the temperature inside and outside the house. Observe how the range is maintained.
But all that would not be possible without having a shed that’s built in the right way.
That means that we must have insulating material in the ceilings and walls. On the ceiling the “R” value must be between 15-19. Nowadays with the infrared cameras it is easier to find the environmental problems of the houses.
So if there is not so much heat input from the house’s construction, we could only work on the heat generated by the birds. On many occasions we are over-ventilating the chicks because of construction problems and not because of the actual heat felt by the birds.
When the chicken is already large, we must eliminate the heat that the bird itself generates. If we do not remove that excess heat due to lack of ventilation, the daily gain of the chickens will decrease. So nowadays, it is better to work with speeds of 3.5-4 m / s.
The second important part for large chickens are evaporative panels. We know that when there is humidity above 80% outside the building, evaporative panels are not very useful. A common problem with evaporative panels is their maintenance, due to the poor quality of the water or the hardness of the water running through them. When the RH outside the warehouse is less than 60%, the evaporative panels can lower the temperatures in the warehouse by 8 to 10ºC. At this point, we must remember the temperature-humidity binomial. When the temperature rises, the humidity drops and therefore during the day due to an increase in the temperature the humidity is lower, which makes it more advisable to use panels.
To put all that in more practical terms, the list below could serve as a guide for Rules of Controlled Environment
- More than 3.8 m / s air speed.
- 1 complete air change in less than 40 seconds
- No more than two degrees of difference from the entrance to the back of the house.
- They must have a good seal in the booth. (> 0.20 pe) They must not have more than 0.20 static pressure. They must have enough air movers to work with half of the extractors. They should look for a difference between the maximum and minimum of no more than 6 degrees in 24 hours with large chicken.