1. Brooding of Chicks
Published on: 06/29/2012
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Author : Leo Antony (Consultant in Poultry Management and Training)
I am afraid I am going to make an eyebrow or two raise when I suggest that the concept of Brooding, as it 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 it’ s due attention and respect and then, translated into a detailed and practical day to day
management. In other words, a manual of standard operating procedures alone will not guarantee good
brooding results, but rather, understanding fully, all the needs of a chick during it’s first three weeks in the
order of their priority and doing things rightly will make a big difference. The HOW and WHEN will, then,
automatically find their due place.
1 WHY BROODING ?
At the outset, we need to understand what goes on inside the hatching egg from the time of fertilization while
the egg is still within the hen and during the three weeks of incubation. Starting with the process of
gastrulation is something like the blue print of the growing embryo, the differentiation of all the organs,
organization of the different systems, maturation and growth of the entire embryo and finally the emergence
of the chick into a new and challenging world, the chick in it’s entirety, needs to be given the necessary
supports to move on from there and develop . Unlike in nature, where stress and disease challenges are
limited and mother hen as well as a free environment provide these necessary supports, intensive poultry
operations are a different ball game. Besides, 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. In other words, the day old chick from the hatchery arrives at the
farm with a great genetic potential but with limited capacity of it’s physiological systems as well as their
functions. Thus, every organ and system needs to be promoted and developed in the growing
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 love to call this responsibility ‘BROODING’. Let us
move on from here.
The Respiratory System, Good Ventilation and Adequate Relative Humidity
If the need is to focus on optimum uniformity, growth of all the internal organs, the immune system , feather
cover, skeleton, the Endocrine system and capacity to eat, digest and metabolize the right amount of feed
for the age and keep growing, then the requirement of oxygen for all these, especially in a broiler and the
heavier breeds of chicken like the broiler breeder, should be given the highest priority. As I mentioned in the
very first line of this article, most managers only consider providing heat as the top most item of 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 it’s healthy requirement of oxygen is through it’s
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. We should know that Carbon Monoxide which is released on burning conventional fuels like charcoal
is, unlike smoke, colorless and odorless and 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 whose list goes unlimited on a poultry farm. 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, please do not always apply only
human standards. To give you example, the human nose can detect the presence of Ammonia in the shed
only when the levels are above 20ppm. whereas levels as low as 10ppm inside the shed can damage the

2. 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 percent 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 wherever birds are grown on deep litter. Unfortunately, there are
very few takers for this fact.
The Immune System and Bio Security:
As we know, 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. The only protection worth it’s name
during the first few weeks before chicks can actively acquire immunity on their own, is 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 Bio security 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 possible 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 harbor and carry hatchery borne infections like Navel or Yolk Sac Infection into your farm. 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 Bio security measures because one can never effectively 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.
The Digestive System, Water and Feed Conversion
The chick takes it’s first drink of water and it’s first morsel of feed only after it reaches the farm. It’s entire
digestive system comprising of the related organs as well as the digestive secretions have, therefore, 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. By the way, 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 is also a good way to build up and develop a healthy and
active digestive system.
The skeletal system in chicks
As we know , 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 feces and is, therefore, not appealing to the eyes of the chick.
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 , therefore, slow in growing. Such chicks should be promptly separated and taken special care of
during the first few days before chicks advance 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.

3. Brooding Temperature and Feather Cover
Day old chicks have no feather covering. What they have is Down which they 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 including general resistance along with the desired immunity,
optimum digestion, good blood circulation, , metabolism etc., apart from protecting chicks from cold. This is
a very important fact to be borne in mind because the body temperature of chicks during their first few days
is several degrees lower than the normal temperature which should be around 41.7 degrees Celsius in a
growing or adult chicken. During the first few days of it’s life, the chick is poorly equipped tp regulate it’s
metabolic process to control it’s 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 plays such a crucial role.
Not the last word:
The reason why I have not listed out any of the conventional do’s and don’ts of Brooding Management that
are generally found in articles on Brooding management, is, that through this paper, I would like to reach
out to poultry managers who understand the chicken well and are knowledgeable in the subject . However, I
am also keen to share my thoughts on concepts that are so often not understood fully or taken for granted -
concepts that can make the difference between AVERAGE and EXCELLENT Brooding results. I only wish
that we poultry managers, like chicken, learn to scratch beyond the surface and keep discovering newer and
better ways, understanding more and doing things right. As Galileo Galilei in his days so aptly remarked :
“ All truths are easy to understand once they are discovered. The point is to discover them “.