Summer of 2016

The summer of 2016 has arrived rather abruptly and with full fury, finding many poultry farmers as well as chicken totally unprepared to face the onslaught. During my conversation with people, I noticed that many are not aware of how exactly summer heat damages and kills birds. I also come across well meant summer management measures that are often either inadequate or counter-  productive.  People do not know why, for example, most birds die from heat stress mostly during the late hours in the evening when the shed temperatures are actually lower than those during the day . Hence I thought of sharing a few thoughts here on what exactly goes on inside the bird when  temperatures rise outside as well as outside the bird.  I hope this help us to understand and handle the problem better.

1. The normal body temperature of a chicken is around 41.5deg.C or 107deg Far.

2. As shed temperature rises above 30 deg. C, the body temperature of chicken also begins to rise.  As this heat increases, it gets trapped deep within the bird and remains there. This heat known as ‘DEEP BODY TEMPERATURE’  or DBT  is the one that will ultimately kill the bird if it is either not prevented or not brought down on time. It is something like the intense heat that one feels inside an egg that has just been boiled and which takes some time to cool down before the egg can be eaten safely. The important difference between a boiled egg that is hot and a chicken with a high DBT is that the egg, once taken down from the boiling water starts to automatically cool, whereas a chicken keeps on producing fresh heat round the clock in addition to what has already been gained and ltrapped inside.

3. DBT generally begins to build up within the bird between 1.00 P.M and 4.00 P.M. when the ambient as well as shed temperatures are at a peak.

4. Chickens gain and build up maximum DBT while consuming and digesting feed, while breathing hot air inside the shed or while drinking water that gets heated in the pipe lines and also from increased activity.

6. If this heat gain is balanced by adequate heat loss, the chicken  can be saved from heat stress. Heat loss can be encouraged by providing cool water, reducing the temperature inside the shed as well as through the use of certain therapeutic agents that form part of summer packs                                                                                                                                                                   

7. Birds generally die due to two effects of heat inside the body:

    a). If the DBT crosses 47deg. C ,which is called Lethal temperature, at any point of time.  This causes sudden death.

    b). If the DBT reaches around or crosses 44 deg. C and fails to come down sufficiently within a few hours’ time. Here, birds die after showing  some indications.

5. Depending on how much  the DBT has reached and how long this DBT remains locked within, birds will either suffer damages or start dying, usually several hours after 4.00 P.M. even though the shed temperatures may have been dropping. This is the reason why most of the summer mortality occur in the late evening and night. Therefore, NEVER STOP COOLING THE SHED OR THE BIRDS IN THE EVENINGS AS LONG AS BIRDS ARE PANTING EXCESSIVELY OR SHOWING SIGNS OF SEVERE HEAT STRESS LIKE DEEP BREATHING,  EVEN IF THE OUTSIDE AS WELL AS THE SHED TEMPERATURES HAVE COME DOWN.

                                                                

1. Do not allow the shed temperature to rise and thereby increase Deep Body Temperatures of birds.  This may sometimes be possible to a certain extent by increasing bird comfort by using fans, foggers, sprinklers or suitable medication like summer packs.              

2.Help the birds to get rid of the Deep Body temperature within the   shortest time possible .                                                                   

3. Do not feed the birds when the DBT is likely to increase or when it is already  high. Symptoms of high levels of DBT in the birds are:                                            
a)  Excessive panting by more than 60 per cent of the birds. This shows that the DBT in most of the birds is crossing around 43 to 44 deg.C .                            
b) Deep breathing by the birds. This is a sign of distress and often the final warning that the DBT is reaching lethal levels and, therefore, mortality is likely to occur any moment.                      

4. Antipyretics or agents that have the capacity to reduce the DBT are best given only after DBT has reached a certain level and not when the body temperature of birds are likely to be close to normal. They cannot work as preventives when they are administered in the mornings before the heat commences.

5. Other agents such as Sodium Bicarbonate, Vitamin C etc. which are a part of commercial summer packs help the bird during heat stress and can therefore, be beneficial as agents that prepare the birds to cope with the effects of heat stress better when used as preventives.

Remember that there are only two main principles one should follow in order to save birds from summer stress:

1-DO EVERYTHING TO PREVENT HEAT GAIN  BY THE BIRD.

 2-ENCOURAGE AND INCREASE HEAT LOSS- DEEP BODY TEMPERATURE.

 No summer management practice should ever violate either of these two principles.

What I have done so far is to merely explain the dynamics of heat stress and the principles on which summer management practices should be based. Farm Managers should find their own trchniques that are practical and  best suited to them, depending on the local conditions and needs.

Give your birds a pleasant summer this year and they will reward you amply.