In large-scale poultry production, environment is a serious issue because it affects the performance of the birds and hence, profitability. Experiments that are well carried out, and the data collected and analysed, reveal ways of reducing costs and/or improving performance with new feed additives or technologies, for example. One of the important facilities for a poultry company is the trial facility or trial farm.
Not just the facilities are important but also trained personnel and qualified scientists to run meaningful trials cost-effectively. Misinterpreting the results may cause more damage than not knowing the answer.
Among the key issues in poultry production performance are growth, performance, cost, product (meat or egg) quality and health of the birds and workers. Each one needs to be monitored and controlled in order to optimise profit and minimise costs. These factors are interdependent, making control even more important.
There are two major groups of parameters to be tested and controlled in poultry production and research: environment and management/husbandry.
Poultry house climate and conditions are well known to have a significant impact on bird performance. These include temperature, humidity, light (day length and intensity), ammonia, carbon dioxide, oxygen, air velocity (speed), solar energy and air quality (odour and dust).
This article will now focus on management/husbandry issues that must be considered when setting up a research facility.
Management and husbandry
Under this category come feed, water, ventilation, static pressure and light.
Feed is one of the important factors affecting the growth and productivity of birds, as well as accounting for the majority of the total production cost.
Feed can be measured manually, and this is feasible with small-scale trials. However, it is time-consuming and may need several people to do the job, as well as to transfer the data to the computer file.
An automatic feeding system is a more expensive option but it is more accurate, faster, and a computer can easily process the data. The outside feed silo can be fitted with a load cell so that deliveries and use can be monitored easily.
For comparative trials where two houses are involved, the silos must be separate and each must have its own system. In pens trials when you have 16 or more pens, each treatment should be linked to one source (bin) of feed with a load cell if there are no differences in location between them.
As feed is consumed, so too is that most vital nutrient, water. A typical feed:water ratio at around 20°C is normally between 1:1.75 and 1:2.00. At higher environmental temperatures, the birds should have access to water throughout the day. Water helps the birds to utilise feed energy, reduce heat stress and lower their body temperature.
Poor water quality, low flow rate and extremes of temperature can lower feed consumption. Low water consumption is often an early sign of a problem in the house or the onset of disease.
Monitoring and measuring water flow and temperature are essential, especially in hot climate or summer season. It is important to know if the drinkers provide the birds with sufficient water at peak times. Monitoring and measuring water consumption and temperature will give a clear picture about what the birds are consuming and when they drink. This information will help improve management and feeding time: for example, feeding time could be adjusted to fit better with the availability of water in the area or outside temperature.
Figure 1 shows a scheme for measuring water flow and temperature.
Water tanks must be insulated and protected from wild birds. They also need to be checked and cleaned regularly to remove any sediment that could block pipes or drinkers.
Underground water storage tanks have the advantage of a more stable temperature, regardless of weather conditions or season.
Information on water flow and temperatures over time will help the manager to predict peak water demand from the birds during the day, as well as an early warning system for problems in the flock or house.
A plan for water distribution to a small trial house is shown in Figure 2.
In air conditioning, heating and ventilation work, it is helpful to understand the techniques used to determine air velocity. In this field, air velocity (distance travelled per unit of time) is usually expressed in metres per seconds (m/s). By multiplying air velocity by the cross-section area of an inlet, you can determine the air volume flowing past a point in the inlet per unit of time. Volume flow usually measured in cubic metres per seconds (m3/s).
To move air, fans or blowers are usually used. They work by imparting motion and pressure to the air with either a screw propeller or paddle wheel action. When force or pressure from the fan blades causes the air to move, the moving air acquires a force or pressure component in its direction of motion due to its weight and inertia. This is why a flag or streamer stands out in the air stream. This force is called velocity pressure. It is measured in inches of water column (w.c.) or water gauge (w.g). In operating duct systems, a second pressure is always present. It is independent of air velocity or movement. Known as static pressure, it acts equally in all directions. In air conditioning work, this pressure is also measured in inches w.c.
There are several ways to monitor and measure ventilation system performance. An easy way is to measure the air velocity of the fan running and then calculate air flow from that. However, the readings will be low and unreliable if the wind is blowing against the fans, or the fans are running at low speed, or the fan is not running at all. Nevertheless, there might still be some air movement. In this case, it is best to combine the air velocity with reading the amps of the motor running the fan. This set-up is shown in Figure 3.
Static pressure is an important parameter to be monitored for normal growing facilities and essential for air distribution and mixing. It is possible for the fan amp sensors to be reading the correct value and the air velocity to be within the range but still there is poor air distribution and mixing.
The only way to know that is by monitoring and measuring the static pressure inside the poultry house. This will help to discover the infiltration problems within the poultry house as well as the static pressure at which the house should be operated to gain the best air distribution and mixing. You may have to operate the shed at upper or lower level of the static pressure recommended range (12-24Pa; 0.05-0.10 inches of water).
A differential pressure transducer (DPT) does this job, and there are several ranges to choose from. The output could be affected by the input power supply as they need a regulated power supply. Figure 4 shows a circuit diagram using a DPT.
Broilers are generally grown using 23 or 24 hours of light each day. Research has shown that programmes with less than 23 hours light can have a number of benefits.
There are three main types of modified lighting programmes for broilers: increasing photoperiod, reduced photoperiod or intermittent lighting. Research has shown that all of these especially increasing photoperiod reduce the incidence of skeletal defects, ascites, sudden deaths and condemnations as well as improving feed conversion and dark meat yield.
To measure the light intensity and duration, you need a light meter and data logger. The data logger should be programmed so that it catches the dark and light periods.
Layout of the trial facility
Planning is the first and most important step in designing a trial farm. It needs to offer efficiency, security, safety, and just like a commercial production facility, it has to meet many, often conflicting, demands. For example, easy and convenient access is needed for vehicles, yet such access may impact security and safety.
Drainage is sometimes overlooked when selecting a site for a trial farm or poultry enterprise. Adequate surface and sub-surface drainage will ensure all-weather driveways and dry foundations and will prevent local flooding. Well-drained soil is essential for satisfactory operation of septic tank drainage and other wastes. Fractured or limestone geologic formations may present as serious a problem as poorly drained soils because pollution may be carried underground for long distances.
Buildings are best located on relatively high ground with surface drainage directed away from foundations.
Figure 5 shows a plan for a simple trial facility offering two rooms (for the treatment and a control), connected by a service room.
As far as possible, the trial farm should be oriented in such a way as to take advantage of prevailing air flow patterns. Orientation must also be considered relative to the transfer of heat from the sun onto the house from exposed roofs or sidewalls. House orientation is critical and is based on heat and ventilation requirements for hot and cold climates. In hot climates, consideration should be given to orienting the ridge of poultry house facility east-west to take advantage of shade provided by the roof overhang.
Winds can blow from all directions, but the prevailing summer breezes and winter winds need to be considered in building planning. As a general rule, winter winds sweep in from north or north-west while summer breezes blow from south, south-west, west, south-east or east. Figure 6 shows the best orientation for poultry houses in the northern and southern hemispheres but it is important to assess the local condition at the site first.