Flocks with access to clean air are more productive, yet all too often the maintenance of ventilation systems is neglected.

Shaun Morris, installation and commissioning engineer at Hydor, has set out the following advice and simple steps that can be taken to ensure healthy and productive birds and how to avoid unexpected maintenance costs.

While an effective ventilation system is now a vital part of any new barn or shed, it won’t be able to operate to its full potential without ongoing maintenance. With budgets stretched, it’s not uncommon for farmers to let ventilation systems slide during the colder months as more emphasis is placed on heat. This can lead to bird welfare issues and reduced returns, as well as unexpected costs when it comes to the peak ventilation seasons of spring and summer. A 12-month proactive maintenance programme minimises this risk.

Undertaking a spring MOT

Spring marks the perfect time to undertake a thorough review of all air movement systems ahead of the summer months. The first thing to confirm is that all of the fans are operating correctly. This includes checking motors, fan blades, fan belts and louvres. With the functionality of the fans confirmed, a thorough audit of the temperature, CO2 and humidity sensors, as well as all of the vents within a shed, can take place.

At this stage, it is really important that those operating the buildings understand how the system has been working for them over the last crop, so that recommendations and small changes can be made in order to give them optimum performance. This type of check can be conducted between each flock and customised dependent on the time of year to ensure all of a shed’s systems, whether that be lighting, ventilation or heating, are functioning as they should be.

Tackling heat stress in summer

Summer marks the start of an ongoing battle to protect poultry against the effects of heat stress, which is a particularly prevalent risk in conditions like those we saw earlier this year. It’s important that ventilation systems are continuously monitored, optimised and, where needed, upgraded to ensure birds are kept within optimum conditions. According to the Department for Environment, Food and Rural Affairs (Defra), an increase in body temperature of just four °C can result in fatality, and it can take as long as five days for birds to acclimatise to high temperatures. Early warning signs of heat stress in poultry include avoidance of other birds, reduced feed intake and increased water consumption.

To tackle the issue, farmers should ensure their sheds are able to draw through as much air as possible. Faults with fans, inlets, control systems and sensors can reduce airflow and lead to heat stress, so a full audit of ventilation systems is essential. If a particularly hot day is approaching, over-ventilating the night before to drop the temperature by between two and three °C can make it easier to maintain optimum temperatures for birds, from 21 days into the cycle, throughout the hottest parts of the day.

As an added measure, some sheds are now being designed with summer inlets at the front and additional fans on the rear. On a particularly hot day, the side vents are closed and the roof fans are shut down to allow the summer ventilation system to take over. This creates a tunnel ventilation effect, increasing the airspeed in the shed and therefore boosting the thermal comfort of the birds. This may not be the answer for every farmer, due to the added upfront cost, but those who do have it, swear by it.

Avoiding wet bedding during autumn and winter

Rapidly falling cold air can cause wet or sticky bedding during colder months, which can lead to red marks or hock burns on the feet and legs of chickens. Thanks in part to the rise in demand for chicken feet in China, there are often premiums available for unmarked feet and thighs and effective ventilation is key to making this possible.

Ensuring side inlets are closing effectively and increasing the air pressure intake to direct cold air to the roof of a shed are two of the ways in which farmers can avoid cold air reaching the ground. Calibrating the air vents to provide a narrower opening draws the air through at a higher pressure, so that it rolls along the roof. Conversely, increasing the vent openings during summer will allow the cold air to drop down to the birds more quickly.

Ventilation often becomes a secondary consideration during the winter, as the number of fans in use can reduce by as much as half. As a result, the audit will focus more on heating and lighting. Checking and replacing fluorescent tubing annually to ensure the correct lux level on the floor for the birds is important, as is the functioning of heaters. One energy-saving technology that had been popular - and is likely to make a return now that biomass incentive payments have reduced - is heat exchangers. In effect, heat exchangers warm the incoming air with the stale air leaving the shed, helping reduce energy costs and avoid issues such as wet bedding.

Increasingly sophisticated technologies are making it easier to understand and control the performance of a given crop. As well as avoiding an unexpected failure in key services when they’re needed most, a regular review of shed systems can help to optimise conditions to ensure the best possible result for a given flock, increasing premium payments and preventing issues such as heat stress and wet bedding.