With poultry farming getting highly mechanised and intensive where birds are confined to inside of buildings for the entire growing and /or production period, high intervention with management practices needs to be observed. Of the key practices, ventilation is crucial as management factor for optimum growth and performance in poultry industry and should not be overlooked as it ranks high in hierarchy of urgency and attention.
Proper ventilation and air quality in poultry farming translate into adequate oxygen and humidity while keeping carbon dioxide, carbon monoxide, ammonia and dust which can be hazardous to birds` health at the lowest level. Good quality air regulates not only exchange of gases, but also distribution of heat in the poultry house. It is therefore very crucial to provide optimal environmental climate for improved growth and performance.
Different types of ventilation methods as employed in poultry houses
Housing plays a critical role to providing a more conducive climate for poultry production and structures constructed take different forms from open-sided buildings with curtains to a mechanically ventilated sheds with extraction fans and insulation pads in place. Cost of erection and economies of a farm however dictates the method a farmer can practice, with most smallholder farmers depending on natural ventilation and large commercialised enterprises going for mechanised type of housing as it suits their financial muscle.
Open-sided buildings which are normally called naturally ventilated houses, are much cheaper to erect. The downplay however can be that since they are dependent on air movement by wind, some ‘still’ summer days characterised by less wind blowing makes this type of ventilation less effective.
It is important to note that in natural ventilation, openings should always allow air in and out, hence adoption of `double` open sided buildings, otherwise a single opening would not suffice. With this type of ventilation, a farmer needs to constantly monitor the climate in poultry houses and act accordingly in adjusting curtains height to allow for optimal microclimate prevalence.
The 4 main roles of ventilation and good quality air include as stated; removal of heat, moisture, dust and built-up of gases such as ammonia. With all the 4 core functions, a farmer need to be aware and take necessary measures to regulate ventilation in poultry houses to avoid unnecessary economic losses.
In regulation of heat
At young age, chicks are unable to regulate temperature by themselves hence most of the time chick rearers are advised to keep brooder houses warm by supplying with external heating sources. Accumulation of heat other than from external factors can be as a result of biological and chemical processes such as respiration, reproduction or digestion. As much as ventilation is very crucial in chick`s health during brooding phase (day1-28 but critically emphasised in day1-14 of chicks life), it has to be provided minimally since at this age chicks are at the very fragile period and can be negatively affected by increased air speed/circulation resulting to unwarranted drafts.
While heat is a key component in growing healthier and high performing chickens, it is much dependent on ventilation for distribution in the poultry house.
In removal of moisture
Excessive moisture in poultry houses results from either licking water points or improper height and limited access to drinkers by birds. Also, birds` excreta moistens the bedding and less ventilation competes against drying. The accrual of moisture content results in bedding harbouring pathogen causing agents which subsequently causes diseases. Horizontal transmission of diseases from one bird to another is made possible by moisture in the poultry house. Moisture also aggravates ammonia build-up which is a threat in poultry health. Diseases like coccidiosis, and other respiratory diseases such as Infectious Bronchitis are more prevalent in less hygienic environments mostly characterised by excessive moisture.
In removal of Ammonia and other waste gases
Ammonia which is a gas formed from the bird`s excreta when bacteria react with uric acid (from waste), should be kept marginal in the poultry house. High levels of ammonia causes obstruction of linings in bird`s respiratory tract making it easy for infections to take place hence ammonia regarded a predisposing factor to many respiratory diseases. Moisture content in poultry houses should therefore be kept minimal to avoid accumulation of ammonia.
In removal of dust
Dust from feed and dry bedding can accumulate in the poultry house and cause breathing complications and respiratory diseases in birds. Sufficient ventilation effectively removes dust either mechanically or by natural ventilation.
With the 4 functions satisfactorily taken into account, disease prevalence and economic losses due to mortalities are holistically addressed.