24 24 LOHMANN TIERZUCHT › MANAGEMENT GUIDE › ENVIRONMENTAL CONDITIONS Environmental conditions Obtaining and maintaining the desired house temperature and environment is an important factor in influencing the well-being and performance of the birds. Table of temperatures at different levels Ventilation There are now numerous types of ventilation systems on the market – positive, negative and tunnel ventilation to name but a few. Regardless of which system you have the aim is always the same: To maintain a stable suitable optimum environment for your flock To do this there are only two points to consider: Air Quality and Air Temperature Positive pressure systems These use mechanical fans to push air into the building and out through strategically placed air outlets. This movement of air creates a positive pressure and can be designed to move air over the birds and help keep litter areas dry. Negative pressure systems These are a combination of open air inlets and mechani- cal fans. When the mechanical fans are operational they create a partial vacuum of negative pressure which will pulls in air from the inlets and expels it out through the fan mechanism. In poor weather conditions this can ex- acerbate poor litter conditions by pulling in cold damp air. In free range systems the systems can be less effec- tive once the pop holes are open. Air quality › Reduce dust and noxious gas levels. › Water leaks, poor litter quality, excessive build-up of dirt, health status, house condition and weather ingress all affect the air quality within the house. › Poor air quality affects not only the general environ- ment but also affects the bird’s respiratory system which will have implications on production capabil- ity and liveability. Tunnel ventilation An option widely used in hot climates where air movement is paramount. Air is drawn in often through a cooling area at one end of the shed. Large exhaust fans in the gable end of the house will draw the air straight through and over the birds ensuring there is consistent air movement. Natural ventilation Natural ventilation is simply allowing an adequate air supply into the building which is controlled by the exter- nal weather conditions. In most cases an air distribution system will be used internally to create an even airflow. The prevailing wind direction, house orientation and location of the site itself will all influence the airflow into the building. Naturally ventilated systems can be difficult to manage in extreme temperatures. Air temperature › While the hens can adapt to varying temperatures where possible, we need to reduce temperature dips and spikes. › A stable temperature between 18–22°C should be aimed for on housing in the production facility. › Humidity can be difficult to control in open houses and particularly those with pop holes and negative ventilation. A relative humidity between 60 – 70% for the first period of development is desirable. Three main areas to focus on are: Temperature & Humidity levels Dust & Toxic gas The best indicator for correct temperature is to observe the behaviour of the chicks!