Optimum climatization in a poultry house

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A house for poultry production is a climate zone where it is crucial to be able to establish and work under conditions which may differ completely from the climate outside. In order to ensure that you have the best conditions to keep the in-house climate then the roof, walls, floors and footing must be properly isolated. It is an absolute necessity that there is a moisture barrier under the floor to keep both floor and footing dry. The moisture barrier makes sure that humidity cannot penetrate the floor, but it is also essential to establish an efficient draining of the entire building land to remove water from the site. If these conditions are fulfilled you can create an optimum climate in the poultry house where your flock will thrive and grow throughout the production period.

Before a new flock arrives you need to make sure that the poultry house has been pre-heated to the desired temperature for at least 24 hours – typically 33-34˚C. The reason for this is that the surfaces in the construction need to be as warm as the air in the house. 6-8 hours before the day old chickens arrive, the litter is distributed in the house.

If the surface in the construction is not thoroughly heated it will submit cold to the air inside the poultry house which will have a negative impact on the day-old chickens and on the quality of the litter. The birds will then have a tendency to clump together and they will use unnecessary energy in the attempt to keep warm. This loss of energy results in increased mortality as well as uneven growth.

Furthermore there will be a condensation in the litter, if the floor temperature is significantly lower than the desired temperature when the birds arrive. As a rule of thumb the concrete floor must be at least 28˚C, when a new flock arrives.

For the day-old birds to maximize their genetic growth potential it is important to create a certain movement of air down by the floor already from day one. This subtle movement supplies oxygenous air to the birds and at the same time removes CO2.

As CO2 is approximately 70 % heavier than atmospheric air the concentration of CO2 will rise significantly in the occupied zone if the house is not properly ventilated from day one. Too much CO2 can repress the development of the birds’ lungs and thus reduce their ability to absorb oxygen. The result is reduced metabolism and lowered growth.

Generally there are a number of physical conditions you have to observe during the production period.

When you want the humidity in the poultry house to be significantly below the humidity in the air that is lead to the poultry house via the ventilation system, it is advisable to limit dehumidification as it is not possible to dehumidify to the wanted level (when it is raining, RH is 100 %).

If you decide to follow the programmed curve for humidity when the RH outside is about 100 %, the climate controller will continue to call for heating in order to dehumidify. This leads to a dramatic increase in heat consumption which in turn increases the need for ventilation as the temperature rises due to the heat added to the house.

The increased ventilation under these conditions may not be suitable in regard to young birds. It may cause draught and can also prompt condensation in the litter. Wet litter increases the production of ammonium. A high level of ammonium gives burnings on the birds’ pads and bodies and generally reduce the welfare of the birds. You spend more money getting lower rent ability. All in all a fool’s bargain!

The above mentioned conditions are depending on circumstances from the outside environment. It’s a physical condition you have to accept and deal with in order to be able to react in due time and avoid the negative consequences by NOT reducing the dehumidification.

DACS’ own ACS6 climate- and production controller has an outdoor humidity sensor. Via measurements from this sensor the ACS6 decides if it is possible to effectively dehumidify the poultry house. If this is not the case dehumidification is automatically reduced in order to avoid the problems mentioned above. DACS is the only company, whose controllers have this functionality. 

We strongly recommend that you follow the pre-set curve for temperature in the ACS6 climate and production controller as this is the curve recommended by most hatcheries. Yet there might be local variations where it is natural to change the settings. If you choose to deviate from the recommended temperatures it may have negative influence on the welfare of your poultry. If the temperature in the poultry house is lower than the recommended your chickens will have to use unnecessary energy to keep warm. The consequence is a higher FCR.

Generally speaking poultry are too often kept too cold rather than too warm. A common mistake is to lower the temperature in the poultry house to make the chickens eat more. What is often forgotten is that a big part of the extra intake of feed is used to keep up the chickens’ body temperature as the surroundings are actually too cold. And as feed costs are significantly more than fuel it is a misinterpreted strategy to lower the temperature – not to say your profitability.

You also need to pay attention to the fact that there is a close correlation between temperature and humidity in the sense that the total energy in the air is a combination of temperature and RH. Just as we humans feel more uncomfortable in high temperatures and high humidity than in hot, dry weather, so do the chickens experience extra strain when both heat and humidity is high. On the other hand it is obvious that a low humidity will make the birds feel colder than what the thermometer shows. Thus a low humidity must be followed by a higher temperature setting to avoid the animals feeling cold. And visa versa.

In periods with warm weather the humidity of the outside air is often low which means – according to the above mentioned – that the comfort temperature is often higher than the temperature curve indicates. The ACS climate controllers from DACS automatically compensate for these conditions ensuring optimum welfare for the birds under all circumstances. If you do not want this automatic compensation or if you do not have the technical control opportunities, you need to keep a close eye on both temperature and humidity in the poultry house to make sure they match the climate curves for optimum animal welfare.