A naturally ventilated house can be scaled to any size. In order to control temperature effectively a naturally ventilated house must be orientated in a north/south direction.
This first part of a three-part series will explore the basics of poultry housing.
The purpose of poultry housing is to provide chickens with a healthy and comfortable environment that’s clean, dry and secure. The most affordable type is a naturally ventilated house scalable to any size.
This doesn’t make use of costly air-conditioning to control the climate inside and does not need to be fitted with a lot of special insulation material.
The most common type of naturally ventilated poultry house is built with the two shortest sides constructed from bricks and the two longer walls from corrugated iron.
These are easily converted to day-range houses which allow chickens to be let out during the day to graze in camps.
Positioning Poultry House
In order to control temperature effectively a naturally ventilated house must be built in a north/south direction.
That is, the longer sides must face north and south, the shorter, brick sides east and west.
As the sun rises, the house is heated evenly and chickens do not compete for heat as a uniform environment is created.
The long sides must also have an opening that runs the length of the house. This helps with the exchange of gasses.
Carbon dioxide for one, emitted from wet chicken litter, has to escape the house as it moves upward.
If it stays trapped it can lead to the growth of harmful pathogens and influence the productivity of layers and growth rate of broilers.
The opening must face north because in South Africa strong winds usually do not come from a northerly direction, and this precaution will also help limit the possibility of a strong wind lifting the roof of off the chicken house.
Chickens do not like wind anyway. Any disruption to their comfort will affect their feed intake and, as a result, their weight gain or egg production.
The opening must be covered in mesh to prevent the entry of wild birds, which can transmit diseases to chickens.
Size
Egg or broiler producers must consider what the size their operation is going to be before they build a house.
A too-large house will need more input costs and require additional equipment and electricity to heat it during cold periods. Rather begin small and build additional houses as production increases.
Each house must be large enough to allow 8m² to 12m² per chicken. If no space is available for movement uneven sized chickens will be raised and they will be more difficult to market.
A chicken house must be built high enough for labourers to walk upright when they’re inside.
Farm location
To avoid high transport costs the chicken house should be within 100km of the abattoir or the point at which the eggs will be marketed.
It should also be located close to medicine and feed suppliers.
The site must be easily accessible by bakkie or truck. It should preferably be built on a slope so that water can run away from the house during rain.
Mud not only affects access to a house, it can be a breeding ground for harmful pathogens.
Various materials can be used, such as brick and mortar, stone or wood, but the material must be easy to clean.
If not, it too can provide breeding ground for harmful pathogens.
Wood, for example, can be used but must be treated and painted as some diseases may ‘lurk’ in cracks if not properly covered.
Temperature Control
There are three ways of heat production inside a house: heat produced by chickens, heat entering a house through the roof and walls and artificial heating.
Chickens are warm-blooded and maintain a uniform body temperature of between 40,6˚C and 41,7˚C.
It’s important to provide young chickens with an ambient temperature of 21˚C to 37˚C (depending on the production stage) and adult birds with a temperature of about 21˚C.
As hot air rises and cold air drops, thermometers measuring housing temperature must be at chicken height or knee height, and not at human eye level, because the temperature at the bottom of the house (where the chickens are) will differ from the temperature here.
A naturally ventilated house makes use of rolls of canvas on the corrugated iron sides that are rolled up or down, depending on whether the house needs to be cooler or warmer. Opening the canvas sides not also helps get rid of gases.
Sprinklers can also be installed on a roof as wetting a corrugated iron roof can help cool down a house.
Always ensure the birds’ temperature needs are being met. A chicken that feels uncomfortably hot will open its wings and stop feeding, and use energy that was supposed to go to weight gain or egg production to maintain its body temperature.
Cold temperatures can be controlled by using infrared lights, brooding systems and spot heaters which heat only a certain area in a house.
Chickens flocking around a heat source means they are cold and need more heat. A cold chicken will eat more to increase its body temperature and will be more expensive to maintain (due to increased feed intake), even though it’s not producing optimally.
When new chicks arrive, create a partition for them. This area can then easily be heated by a spot heater. This saves electricity as the entire house does not have to be heated.
Broilers produce more heat as they grow very fast and will therefore need less artificial heat. Larger, older birds and active birds, like free-range birds, also produce more heat.
If all factors work in favour of chickens, the end result will be a uniformly sized chicken the market wants.
