The use of and reliance on automated systems is steadily increasing. But monitoring bird behaviour remains the best way of determining if the environment within a house is correct. Regularly observing bird behaviour by the same person is essential. He must use all senses and respond to the signals that the birds give.
By John Powley, global project manager, Technical Transfer Team, Aviagen UK
The ever increasing pressures on improving financial returns for the broiler grower have resulted in fewer personnel on the farm and an increased reliance on automated, computer-based environmental ventilation systems. Nevertheless, the need to identify and respond to the birds' requirements in a timely manner stays as important as before. Stockmanship is key to good bird performance and welfare. The best way to do this is to spend time in the poultry shed observing the birds and responding to the behavioural signals they give. Stock sense and the ability to understand what 'normal' behaviour is for a flock is a key part of good broiler flock management.
How often are standard operational protocols, which list or even dictate the required set points of the environmental systems, followed and implemented without any attention being paid to the bird and what it is telling us?
Observe the birds
Often automatic environmental systems will go out of harmonisation and require re-calibration or adjustments. This can easily be missed if time is not taken to observe the birds and their behaviour. Even when automated systems are working correctly, the only way to truly determine if the environmental conditions are correct for the flock at any one point in time is to observe bird behaviour. Ultimately, growth rate, FCR and liveability will reflect the environmental conditions a chicken is exposed to. And ignoring these behavioural signals can negatively impact on the flock's performance. A good stockman uses all of the five senses to determine if the birds' needs are being met by the environmental conditions within the house (Figure 1).
The environment of the house and bird behaviour should be observed at various times of the day by the same person. Observations can be done at any time day to day management activities are completed, but, importantly, some specific inspections just to monitor flock behaviour should also be made.
Start before entering
Observing the flock and the environment starts from even before you enter the house. Before entering the house it is important to have an idea of what the internal housing conditions and the expected systems operation should be. If the environment is different to expectations, this is the first indication that there may be a problem.
As you open the door of the house, be aware of how the door opens. Does it open with slight resistance, no resistance or high resistance? This will indicate the air pressure within the house and reflects the ventilation settings. If resistance is high, it suggests that the negative pressure within the house is high and therefore air flow may be too high. No resistance when opening the door indicates negative pressure may be too low and air flow may be poor.
Visual observations of the birds will give a good indication of the adequacy of the environment the birds are exposed to and the initial view of the flock's distribution will act as a good signal of their comfort level.
Upon entering the house stop and look at the flock, noting how they are distributed around the house. A uniform bird distribution across the house is the goal and this is chiefly affected by temperature and air speeds associated with the operating house pressure. The negative pressure (and incoming air speed) should be enough to 'throw' the incoming air to the middle of the house where it will be mixed with warm in-house air before falling back down to bird level. Thus the ideal operating negative pressure of a house does vary and is based on the following:
- Width of the house (distance the air must travel from the inlet entry to the peak of the house)
- Angle of the internal ceiling
- Shape of the internal ceiling (smooth or with obstructions)
- Type of inlet used
- Amount the inlet is opened.
If the ventilation system is working correctly and there are no air leaks in the house, the operating negative pressure for an age (and ventilation) will be correct and bird distribution across the house will be uniform (Figure 2).
Too low or too high
If any of the following bird distribution patterns are seen, there may be a problem with the ventilation of the house that needs to be resolved. If negative pressure is not correct (low), cold air from outside will fall directly on to the birds causing discomfort and potential litter quality problems. If this happens, the birds will migrate away from the area where the cold air is directed. In this situation the air inlet opening has to be reduced or the fan speed increased to ensure that the incoming air is directed along the ceiling surface (Figure 3). Conversely, if negative pressure is too high, a wind chill effect may occur in the middle section of the house. In this situation the inlet openings should be increased (Figure 4).
If fan speed is not correctly matched to the air inlet openings, dead spots within the house with little or no air movement will be created. In this situation there will be specific localised areas where the birds have migrated away from. To correct this, specific air inlets will require adjustment.
Any cold air or draught spots which cause birds to migrate away from an area of the house will result in higher stocking densities in other areas of the house, increasing pressure on feeders and drinkers as well as, potentially, nest space.
As a rough guide, approximately one third of the flock should be feeding, one third drinking and one third resting at any one point in time. These behaviours will be disrupted if environmental temperatures are not correct. If the temperature is too hot an increased number of birds will be seen resting or congregated around the cooler side walls of the house. Increased numbers of birds may be at the drinkers.
If the environmental temperature is too cold, birds may be huddling together and the number of birds feeding and drinking will be reduced.
Use all senses
After the initial entry into the house and observation of the flock, slowly walk the length of the entire house, using all the senses to assess the bird's behaviour and its environment. Walking the entire house is important to ensure that there is minimal variation in the environment and bird behaviour throughout the house. When walking through the house get down to bird level. Does the internal atmosphere feel stuffy (humid), is the ammonia level starting high, are birds breathing heavily? Any one or a combination of these points possibly indicates that the minimum ventilation rates require increasing or that there is a localised air distribution issue, e.g. air inlet may require opening further.
Make an assessment of what the temperature of the house is like. Are there any draughts, are birds avoiding any particular areas of the house? How do the birds move away as they are approached? What calls and sounds are they making? Each of these behavioural characteristics provides important information about the comfort of the birds in the house.
Remember that no two flocks or houses are the same. Each will require the individual interaction of the stockman with the environmental system set points based on the behaviour of the birds. By frequently monitoring the behaviour of the bird, normal behaviour for the flock can be identified so that any changes from that norm can be easily and quickly identified and environmental set points adjusted to achieve optimum performance both economically and biologically.