All animals show fear and stress and as their keepers, it should alert us to their needs. Paul Donovan investigates how to reduce stress in poultry.
One of the best definitions of fear, is that made by the well respected poultry scientist R. Jones. He defines it as “an adaptive state, with fear behaviour functioning to protect the animal from injury.”
Essentially, what he is saying, is that fear is a protective mechanism to an external stimulus such as danger, or harm; whether that be real or perceived. Fear, is a mechanism which helps keep an animal alive, and can be innate (born with) or acquired (learnt).
Jones goes on further to say: “Fear is often adaptive in ideal circumstances, but neither we nor the animals in our care live in a perfect world. In reality, many farming systems prevent the animals from responding in an adaptive fashion to potentially threatening stimuli. In these circumstances, fear can be a powerful and potentially damaging stressor, particularly if it is intense or persistent. Minor fear within tolerable limits will do the bird no harm. But both acute and chronic fear can seriously harm welfare and performance of poultry”.
Factors which interfere with the well-being of the bird are called stressors, or stress factors, and the result of the response, or its effort, to that bird while trying to cope with the stressor, is what constitutes stress. A stressor can be any number of things, ranging from tension, anxiety, worry, fear, uncertainty, problems, threats, discomfort, pressure, strain, challenge, difficulty, distress, hardship, burden, effort or struggle.
Chicks will show different levels of fear to those of adults. Part of this is due to the growing up process. A chick may show no fear to being picked up, because it does not perceive any threat in that action. Try to pick up an adult chicken which has never been handled before, and it may have you running around the hen house like an Olympic sprinter. This is because it is now more aware of the environment around it, and its survival instinct kicks in. Running away is a survival instinct born through unfamiliarity. However, the more we pick up that chicken, the more it becomes habituated to that action, because it knows nothing is going to happen to it; hopefully.
BASIC ACTIONS CAN CAUSE FEAR
The same can be said about the basic actions we carry out around them. Some months back I acquired ten new point of lay Lohmann Silver-brown hens. As I introduced them into the enclosure, nothing was familiar to them. They didn’t know where the feeders or water were. They had to become accustomed to their surroundings. This also included basic husbandry on my part. Every time I entered the enclosure with a rake to give the flooring a once over, the birds would go ballistic; kicking up a racket and ‘cowering’ in the corner. They perceived me and the rake as a threat and something to escape from. After several weeks, they became accustomed to both, and now view the rake as a feeding tool. They know when I go into the enclosure with it, I’m going to rake the substrate which exposes hidden food they can peck at which they have great delight in scratching over. This shows that an animal subjected to a perceived negative response on a continual basis, will soon become accustomed to it, and eventually view it with a positive meaning.
This can happen in just about every aspect of the bird’s life; with the exception, perhaps, of a predator such as a cat or fox. I am sure they never really trust those no matter how accustomed to them they may become. Responses to fear will manifest themselves in two basic forms; behaviourally and physiologically. Because I live in a country with a healthy snake population, it is interesting to see how my hens respond to the presence of a snake. They become noisy (they have a very distinct snake warning vocalisation) and agitated, keeping their distance until they have evaluated the threat. Some individuals are less fearful than others, and will move in to have a peck or two. If the snake is small, the reticent birds will eventually follow the bolder ones, and pile in eventually killing the snake. If the snake is a large python say, even the most forthright bird will shy away.This is because they now recognise the snake as being more of a danger to them.
Another common behaviour is to freeze. At the first sign of danger, whether from the ground or the air, the bird will squat its rear end down on the ground and flatten its back, or flatten itself as if in a resting position. It will remain motionless, but alert to the perceived threat. Such a posture may make the bird feel less vulnerable and so reduce its level of fear. It is easy to evaluate behavioural responses, as they display themselves as physical actions, so it is possible to see that a bird is stressed. What is not so apparent are the physiological responses. These are the things which are happening inside the bird. On exposure to the fear precursor, as with any other animal, adrenaline will be released which begins to surge through the bloodstream. This increases the heart rate and energy levels. If the fear level is high, Corticosterone is then released into the bloodstream. One of the effects of its release, is to boost levels of glucose in the blood, allowing the bird to access high levels of energy over the short term. With this it can make an appropriate response such as running away or taking flight. Short term exposure to the threat stimulus, and access to high levels of glucose will not adversely affect the health of the bird. However, long term exposure to the stimuli, and high levels of Corticosterone can invoke what is called a chronic stress response. This can be harmful to the bird and its welfare, and so should be avoided at all costs.
Lighting has also shown to affect stress and fear in chickens, irrespective of the bird’s age. When subjected to 24 hours of light, this results in sleep deprivation, and higher stress and fear levels than those subjected to ‘normal’ lighting levels. In view of this, one should avoid using any form of incandescent, or fluorescent lighting over a sustained period of time. If rearing chicks, or if birds require additional lighting, a red lamp should always be used.
As we have seen, fear through mistreatment can come in many forms, and a hen which is subjected to it on a constant basis, will respond to it many different ways. Perhaps the most evident, is a reduction in egg production, erratic laying, or eggs with poor quality shells. At the same time she may suffer weight loss, leading to poor feather condition. Depending on where she is in her growth cycle, young birds may experience a slowing down in growth rate. In a commercial operation, all of these can impact negatively on profit margins, and so it becomes important for the poultry producer, or chicken keeper, to limit those elements of husbandry, or production techniques, which create fear or stress in the birds. The actions of an aggressive poultry worker who mistreats birds will soon be picked up by the flock. Once the hen(s) stop laying, the natural action by the owner, is to cull that/those individuals, on the basis of lower egg production, without realising the tailing off is due to a stress factor. In this case mistreatment.
REDUCING FEAR
As many responses to fear are physical, reducing them can easily be achieved, and should be part and parcel of basic care. For example, working quietly and peacefully around the birds, and keeping boisterous children, who do not understand the consequences of what they are doing, at bay. Keeping family pets such as cats and dog away from the birds should also be a prerequisite to their happiness. Fido chasing a bird around may be entertaining for some, but it is not for the hen. They are not playing. As far as the hen is concerned, it is extremely stressful. On a more practical front, there are three universal approaches towards fear suppression. These are enrichment, genetics and, more recently, the use of vitamin supplementation.
ENVIRONMENTAL ENRICHMENT
Environmental enrichment is the approach where we stimulate the birds through behavioural motivation. Basically, what this means, is giving them something to do, and keep them motivated. Alleviating boredom not only reduces the likelihood of bad behaviour, but has been show to reduce fear and stress. Environmental enrichment predisposes the birds to varying levels of familiarity, and the more they become familiar with something, the less stressed and fearful of it they are. As I have demonstrated with the rake, as soon as they became accustomed to it, they viewed it in a positive light. Another way I could have done this, would have been to leave the rake in with them, and they would have gotten used to it that way. But I wanted to put an association on the rake and me, so that when it moved, it was viewed in a positive action. A static object and a moving one can foster two entirely different reactions. Interestingly, if I now go in with a different coloured rake, my hens react in the same way as for the original rake. They view it as ‘feed time’.
INTERACTIVE ENRICHMENT
One of the easiest forms of reducing fear, is to interact with your birds. I routinely sit with my hens, which allows them to become accustomed to me in a different way. I will sit there and offer them food by hand. I will also give them a feather “massage”, by stroking them on the back. Some are responsive to this, while others not so. This type of interaction gets the hens accustomed to your hands, and being touched. One of the benefits of a calm bird which is used to being handled, is when veterinary treatment, or medication needs to be administered. A calm bird will not struggle and be easier to treat. There is also some evidence pointing towards medications/vaccinations working more efficiently when administered to a stressfree bird.
VITAMIN SUPPLEMENTATION
We all know the benefits of a balanced diet, and the advantages of taking vitamin supplements, but recent studies have shown, that adding vitamin C to hens drinking water can quieten them down, and increase their adaptability to fear. It works by the metabolism of the amino acids which are involved with stress. In a persistent or forceful state, fear can be inherently harmful. In fact, it can be a silent killer. It is a precursor to many negative welfare issues, and in many cases can affect productivity performance. How the bird(s) physically react to fear are many and varied, but tend to be in an intense violent manner where they attempt to escape the perceived threat. In a free-range environment this may not be a problem, but in the confines of a hen house, or wired off enclosure, the birds could seriously injure themselves. As poultry keepers, whether commercial or hobby, we should be striving to provide as stress-free-an environment (physically and emotionally) for our birds as possible, as this will maintain them in a positive emotional state. Doing so, eliminates their overreaction and inappropriate response to a negative action.
GENETICS
Fear has been shown to be linked to genetics, with some breeds more susceptible to it than others. A logical step, would be to genetically modify those breeds which exhibit fear, to create less stress-free birds. In a commercial operation, less stressed, or quiet birds will produce more eggs, Unfortunately, while genetically modifying birds to create a more stable breed could solve a lot of behavioural issues, it can take a long time for research to filter down into the mainstream. And could take years before the ‘norm’ for a particular breed becomes widespread. Until then, we should rely on more practical approaches to solve the issue.
TAIL-END
Whether in a commercial operation, or the home environment, for the benefit of the bird(s), the factors contributing to fear should be investigated and rectified. While in small doses, fear is a survival instinct, continual exposure to it at a high level will be detrimental to the birds health, and the profitability of a commercial operation. Perhaps one of the biggest threats in the home environment, is that made by family pets, and unsupervised children.
REFERENCES: Jones, R. B. (1996). Fear and adaptability in poultry: Insights, implications and imperatives. World’s Poultry Science Journal A distinctive warning call is given to a snake 52, 131–174.
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