Air circulation and temperature in the cage have a vital role in closed house. Without proper ventilation management, it is impossible to achieve good chicken performance. Thus, air circulation and temperature support, such as fan and evaporative cooling pad, must be considered.
Minimum ventilation is the minimum air needed to replace the air in the cage so that it remains optimal for the broiler. Minimum ventilation provides adequate oxygen (O2) and removes moisture in the house. Excess moisture can increase ammonia levels (NH3) and cause wet husks, thereby increasing the risk of disease in chickens.Minimum ventilation requirements must be met in a closed house. One symptom that occurs if the minimum ventilation is not met is the uneven distribution of the chickens.
Chicks for up to 14 days have not been able to regulate their body temperature properly and chicks for up to 7 days should not be exposed to wind from fan, however minimum ventilation requirements must be met.
Number of running fan (for min. ventilation) = Total volume requirements = fan requirements
Calculation example :
Determine the number of fan lit required for a population of 10,000 chickens broiler age of 1 week with a fan capacity of 2.000 m3/hours?
- 1 week old chickens needs = 2,8 m3/1000 chickens/minute
- Minimum ventilation requirements = 10.000 chickens x (2,8 m3/1000 chickens/minute) = = 28 m3/minute
- Convert fan capacity unit to = (2.000 : 60) m3/minute = 33.3 m3/minute
Number of fan running = 28 m3/minute : 33.3 m3/minute = 0, 84 fan ≈ 1 fan turn on
Guidelines turn on the fan
After the chicken is 2 weeks old, chickens begin to generate their own body heat. To produce a high weight, broilers need to release heat from their bodies so that they avoid excess heat.
Guidelines for calculating the number of fan running on broilers 2 weeks old until harvest are shown in the following formula.
Calculation example :
Size closed house cage :
Length = 100 meter
Width = 12 meter
Height = 2 meter
Using a fan with a capacity of 31.300 m3 / hour. If the chicken is 17 days old, and the environmental conditions at that time are known :
Temperature = 30.5OC
Humidity = 70%
Determine the number of fan running for the closed house cage!
Step 1 :
- Broiler 17 days requires the effective temperature of 28OC (Flash News Edition 1)
- Based on the environmental temperature conditions of 30.5OC , %RH = 70%, and the effective temperature required for chicken is 28OC, then wind speed of = 1 meter / second.
(Guide to wind speed table see Flash News Edition 1)
- Convert fan capacity units to = (31.300 : 3.600) m3 / second = 8.7 m3 / second
Step 2 :
To create a uniform air speed in the cage, the fan numbering needs to be considered. The alternate and frequently used fan numbering is shown in figure 2.
Regular maintenance of the fan will certainly improve life span on the fan and prevent any damage while operational. Some things that need attention in the care of fan :
- Clean the fan belt and fan blade with soapy water before the chick-in.
- Before chick in, make sure the fan belt tightness & fan motor rotation, so that the wind speed produced by each fan is uniform.
- The maximum wind speed in the cage is 3 meters / second. Wind speeds that are too high can blow away the husk dust so that it can cause respiratory problems in chickens.
Guidelines to using the evaporative cooling pad
Evaporative cooling pad functions to cool the incoming air by utilizing water evaporation. During the brooding period, it is recommended that the evaporative cooling pad pump is not operated. Running the evaporative cooling pad pump can produce air that is too cold for the chicks during the brooding period.
The evaporative cooling pad pump is operated only if the temperature in the house is above 28°C and the chickens are over 14 days old. It should be noted that operating the water pump on the evaporative cooling pad will have an impact on increasing air humidity. Farmers are not recommended to wet the cooling pad when% RH is above 75%.
The highest air velocity is near the cooling pad. Therefore, the brooding circle is located in the middle of the cage (not near the cooling pad). The separation distance serves to prevent chickens from excessive windchill effect (preventing chicks from chilling).
Evaporative Cooling Pad Maintenance
Evaporative cooling pad that is often wet with water and exposed to sunlight will risk the appearance of moss on the cooling pad body. To prevent this, it is necessary to spray the evaporative cooling pad at least once every month using a disinfectant solution (such as Medisep). Disinfetkan solution will prevent the growth of algae and bacteria on the cooling pad. Use a low pressure spray and not a high pressure spray when cleaning the cooling pad.
Guideline to using the cooling pad inlet curtain
Evaporative cooling pad is equipped with a curtain on the inside of the cage. The cooling pad inlet curtain functions to regulate the air opening into the cage.
The air inlet gap is opened from the top of the cooling pad inlet curtain. The size of the inlet air gap or the cooling pad inlet curtain opening is adjusted to the desired air speed in the cage. Generally, the cooling pad inlet curtain opens around 60 – 80 cm to produce an incoming air speed of around 1.8 – 2.5 meters / second.
The importance of maintaining an electricity supply
The electrical factor has a great potential to cause cases in closed enclosure systems. If a power outage occurs, the oxygen supply will be insufficient and dirty and humid air will be trapped in the cage and endanger the health of the chickens.
The solution to dealing with power outages is to lower the cage curtain manually or automatically using the Emergency curtain drop tool. Emergency curtain drop devices are installed on each side of the cage curtain near the cage curtain pulley.
Signs of a problem with ventilation
The uneven air flow in the house causes disruption to the growth and performance of chickens. Therefore, observe the behavior of the chickens and around the coop for ventilation problems that occur :
1. Chickens gather in the middle of the coop or seem to avoid the edges / sides of the cage
This is because the wind speed is too slow. Generally, the wind speed conditions are too slow to be found on the left and right sides of the cage, causing the temperature on the left and right of the cage to be hotter than in the middle of the cage. Therefore, chickens will tend to avoid the hot areas (also known as dead spots).
This problem can be overcome by reducing the gap in the cooling pad inlet curtain opening or modifying the roof where the roof is given a ceiling. With the installation of the ceiling, it can be avoided that hot air that collects in a windless flow area.
2. Chickens gather on the left and right sides of the coop & tend not to move or sleep much
This sign is caused by wind speed that is too fast or strong, which has a large windchill effect, so that the chicken becomes cold. Chickens that are cold will reduce their activity so that energy from the feed is not wasted for mobile activities, and is used to heat their bodies. Thus, it will have an impact on reducing feed intake and slowing the growth of broilers.
This can be overcome by widening the gap in the cooling pad inlet curtain or turning off some fan that are running. Make sure that the effective temperature required by the chicken is reached.
3. Uneven distribution of chickens
The uneven distribution of chickens indicates uneven house temperatures. Uneven cage temperature can be caused by air holes. Holes in closed house cages are a big problem.
Air holes also cause other problems :
- Creates multiple areas with minimal airflow (“dead areas”)
- Hot and humid air will be in the inlet, outlet and cage sides
- The working power of the fan is getting heavier because it has to draw air from the leakage holes
Locations that need attention because air holes often occur are:
- Cage curtain joints
- Top floor truss (air holes from second floor to first floor)
Perforated cages normally have a minimum of 25 pa (pa) of static pressure. A device called a manometer can be used to measure air static pressure.
4. Wet Husks
Chaff that is wet or damp indicates wind speeds that are too slow. During the production period, a lot of gas and water vapor is generated. 80% of the water that is drunk by the broiler will be excreted as water vapor which must be removed from the cage. Water vapor that is not wasted through the vents will be absorbed by the husks and cause the husks to wet.
5. Terrible Smell
One of usual problems at the chicken farm was the smell of cages. Strong smelling cages ares usually caused by high level of ammonia gas. Ammonia gas has a high irritation power, especially to the mucous membrane in the eyes and respiratory tract of chickens.
When we enter the cage and the smell of ammonia has been smelled, it means that the ammonia level is above the threshold (> 20 ppm). Beyond this safe threshold, ammonia will cause harm to chickens, both in the form of damage to eye and respiratory membranes.
Several causes of increased ammonia levels:
- The air circulation system is blocked
- The cage density is too high
- Less than optimal litter management
- Chicken feces is wet
Therefore, some steps to prevent an increase in ammonia levels are to:
- Air circulation regulation
- Set the appropriate cage density.
- Good litter management (carry out regular litter flipping every 3-4 days and pay attention to leaks from the chicken drinking area)
- Check and improve the nutritional quality of the ration (so that the feces are not wet).
CPI PE. 2016. Membangun Kandang Closed House.
Cobb. 2012. Broiler Management Guide.
Artikel: Evaporative Cooling Systems: How and Why They Work (Mississippi State University; 2013)
Marteen de Gussem. 2015. Broiler Signals (halaman 27). Netherlands: Roodbont Publishers.