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Brooding of chicks – An art and a science

This article does not list the conventional do's and don'ts of brooding management. The idea is to reach out to poultry managers who understand the chicken well and are knowledgeable in the subject. However, thoughts are shared that are so often not understood fully or taken for granted - concepts that can make the difference between average and excellent brooding results. Poultry managers, like chicken, should learn to 'scratch beyond the surface' and keep discovering new and better ways, for doing things right.

By Leo Antony , Poultry staff trainer, Suguna Foods, India
The concept of brooding, as is traditionally believed, should not be limited merely to the practice of providing heat, feed and water to day old chicks. The science of brooding comprises of a more holistic approach where every need of the day old chick is given its due attention and respect and then, translated into a detailed and practical day to day management.
At the outset, we need to understand what goes on inside the hatching egg from the time of fertilisation while the egg is still within the hen and during the three weeks of incubation. The chick in its entirety needs to be given the necessary support to move on from there and develop. With mounting genetic improvement in poultry breeding, it is mandatory to exploit every bit of the entire genetic potential of the bird by fully understanding and supporting the physiological activities of the chick. Therefore, the focus as well as the efforts during the first three to four weeks should be on laying the foundation for good uniform growth of body tissues, a healthy immune system, an active endocrine system, a supporting body frame or skeleton, the capacity to eat, digest and convert the right amount of feed for the given age and finally, a good feather cover. I would call this responsibility or better still, the opportunity -‘brooding’.
The respiratory system
If the need is to focus on optimum uniformity for growth of all the internal organs and systems the requirement of oxygen, especially in a broiler and the heavier breeds of chicken like the broiler breeder, is paramount. Most managers only consider providing heat as the highest priority because people tend to equate brooding with providing heat. It is needless to mention the extent to which a chick that is approximately 40 grams in weight is expected to develop in the next three weeks. Complex physical as well as chemical reactions take place within the chicken and this process consumes loads of vital oxygen.
The only way in which a chick can get its healthy requirement of oxygen is through its respiratory organs which basically are the trachea, bronchi, lungs and the air sacs. During the period of brooding, it is important to protect these organs from pollutants like microorganisms, dust and toxic gases including carbon monoxide, carbon dioxide and ammonia. People who neglect these areas end up seeing respiratory as well as other metabolic problems like ascites, etc. to which fast growing birds are naturally prone. Carbon monoxide which is released by burning conventional fuels like charcoal has, unlike smoke, no colour and no odour and is more hazardous as it seriously interferes with the oxygen binding process. Contamination of the brooding shed by these pollutants not only depresses growth, but also leaves the growing chick with a damaged and faulty respiratory system that later on predisposes birds to all types of respiratory complications.
Caring managers require a good level of sensitivity and judgment when it comes to curtain management in open sided houses. When considering ventilation and temperature management, do not always apply only human standards. To give you an example, the human nose can detect the presence of ammonia in the shed only when the levels are 20ppm or above. Whereas levels as low as 10ppm inside the shed are suspected to damage the chicken’s delicate respiratory tissues as well as the conjunctiva. What, when, and how much the chicks need should be the deciding factor.
A minimum relative humidity of 70% or even up to 80% helps both in preventing dehydration, and in maintaining a healthy mucous membrane in the respiratory tract which acts as a protective barrier against pollutants including pathogenic microorganisms. Measuring relative humidity regularly in brooding and growing houses also helps the timely cycling of coccidial oocysts from the vaccine and provides valuable indication of the moisture levels in litter when birds are grown on deep litter. Unfortunately, there are very few takers for this fact.
Immune system and biosecurity
Chicks come out with a very limited immune system whose capacity grows only with age and the ensuing vaccinations that follow during the entire growing cycle. During the first few weeks they have to rely on the maternal immunity which is provided through the hatching egg. Even this is not always reliable. If you wish to have a growing or laying flock with a consistently protective immune status, one way is by ensuring that the supplier hatchery guarantees chicks that are free from hatchery borne infections, which are manifold these days. The second is by enforcing a code of strict biosecurity on the farm. There is no substitute for these two critical factors. Infections at a very tender age of the chick are immunosuppressive and are a cause for perennial problems throughout the cycle of the flock. To put it in very simple terms, the immune system needs to be trained as birds grow in age and an untrained immune system, like an untrained soldier, is prone to serious injury and possibly, death from attacks. Besides, any amount of cleaning and disinfection of the brooding shed before the arrival of chicks becomes futile if you bring in a batch of chicks that harbour and carry hatchery borne infections like navel or yolk sac infection.
Once pathogens enter the brooding shed, they find the best of conditions in which to live, grow and multiply and, therefore, come to stay in the poultry house for good. In such a situation, if we happen to see recurring bacterial or other infections in your chicks or growers, we cannot blame only the drinking water or air or even possibly our own biosecurity measures because one can never eff ectively disinfect litter or droppings that have already been contaminated. Among other factors that suppress immunity in chicks are severe stress, toxicity in feed and high levels of ammonia in the brooding shed.
Water and feed conversion
The chick takes its first drink of water and its first crumb of feed only after it reaches the farm. Its entire digestive system has very limited capacity for digestion and metabolism. We therefore have to ‘train’ this particular system by stimulating water and feed consumption in that order, especially during the first few days of the chick’s life. Some caring managers have the practice of ensuring good feed intake in very young chicks by doing a ‘crop fill test’ which consists of checking the percentage of chicks with full crops as well as assessing the extent to which the crops are full. An active digestive system with the necessary secretions also greatly contributes to the early and optimum cycling of the coccidial oocysts wherever vaccination for coccidiosis is employed during the first week in the chick’s life. The system of feeding very young chicks several times a day is also a good way to build up and develop a healthy and active digestive system.
The skeletal system
A major portion of skeletal growth in a chick is completed by about 12 weeks and the initial three to four weeks form a significant part of this period. Where chicks are fed on plates and in open feeders during this period, it is a common practice to discard the powdery portion of the feed because it is often contaminated with the litter material and faeces and therefore is not appealing to the chick. However, it is precisely in this powdery part of the feed that the essential vitamins and minerals so vital for skeletal development are present.
It is also normal to see a percentage of chicks with signs of weakness or small in size and slow in growing. Such chicks should be promptly separated and given special care during the first few days before the flock advances in age and it is too late to correct the development pattern. We should remember that it is more difficult to manipulate bone growth than body weight. Chicks with a poor or slow developing skeletal frame naturally are slow in body weight gain and therefore tend to develop fat tissues rather than muscles. This is absolutely true especially in broiler breeder flocks.
Feather cover
The down on day old chicks is quickly shed, as feathers start growing from the first week onwards. A healthy feather cover helps to conserve body temperature and thus saves precious dietary energy which would otherwise be diverted for preserving body temperature at the cost of body weight gain. Good feathering helps the chick to maintain the right body temperature which, in turn, promotes all other functions. This is a very important fact to bear in mind because the body temperature of baby chicks is several degrees lower during the first few days than the normal body temperature which should be around 41.7°C in a growing or adult chicken.
After hatch the chick is poorly equipped to regulate its metabolic process to control its body temperature sufficiently. It therefore, depends on the environmental or brooding temperature to maintain the optimal body temperature. Moreover, it takes almost three weeks for a chick to reach a constant and stable body temperature. It is here that providing and maintaining the right brooding temperature at chick level in the house plays such a crucial role.

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Leo Antony , Poultry staff trainer, Suguna Foods, India

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