Q&A: Poultry health at housing
31st August 2022
This month, avian vet Suzy Brown, of Avivets in Cheshire, offers advice on optimising the health of housed poultry this winter.
Q: What diseases will housed poultry be more susceptible to this winter?
A: Typically, winter can pose more respiratory disease challenges than warmer and drier times of year. When poultry are continually housed, disease transmission is easier so producers should remain vigilant for signs of the common poultry respiratory infections such as infectious bronchitis and mycoplasmosis. Obviously, avian influenza has been especially problematic over the last couple of winter periods and unfortunately it is one of the respiratory diseases that thrives in cooler damper conditions.
Free-range producers should remain vigilant in managing worm burdens if their birds must be housed. Sometimes, there is a misconception that because birds are not going outside, they won’t be susceptible to worm infestation. This isn’t always the case so producers should uphold vigilance against worms and speak to their vet if they’re unsure about the worming status of their housed flock.
We tend to think of wintertime as a cooler period, especially for naturally ventilated buildings. This can reduce red mite activity. However, even in small amounts, this parasite is an excellent vector for disease as well as placing a significant stress on the bird. If free-range poultry must be housed, ambient shed temperatures can be slightly warmer. This will favour red mite replication so producers should continue to monitor red mite populations throughout this period and treat accordingly.
Q: How could the temperature in sheds impact lifelong gut health?
A: Poultry like and perform well under constant conditions. Extremes or wildly fluctuating temperatures are particularly stressful for birds and this directly impacts on their intestinal health. This in turn impacts on their productivity. Prior to winter, it is imperative that all temperature and humidity recording equipment is working accurately and reliably, especially where this technology is needed to run the ventilation system of the shed. Any broken or poorly functioning ventilation equipment should be replaced. Producers should be aware that over time, equipment won’t always be performing to the same degree it did when it was brand new. If producers are unsure whether the shed’s climate control systems are working properly, consider ‘smoke’ testing the shed so that air movement can easily be seen, to help identify areas that require attention or repair.
Q: What are the risks of insufficient ventilation?
A: Disease as well as poor growth rates are more likely where insufficient ventilation is a problem. Not getting enough oxygen, but conversely not removing enough waste gases such as CO2 will prevent birds reaching their genetic potential in terms of performance. Usually, it makes managing their environment more difficult, largely due to excessive amounts of water vapour being present within the shed. Consequently, a bird’s respiratory system has to work harder and this stress alone will increase susceptibility to disease. Some waste gases can directly damage the respiratory system too. Poorly ventilated sheds can be dusty and mildly noxious which impacts on human health and willingness to work in the poultry shed. Staff should be encouraged to wear masks when working in poultry sheds and noxious smells should never be allowed to accumulate from a human, as well as bird perspective; a high waste gas concentration can affect bird vision and suppress feed intakes.
Q: What are the risks of high humidity?
A: Relative humidity should be managed according to breed and species requirements and in accordance with audit body requirements. Excessive humidity can increase the risk of most diseases. Mould on bedding and feed is often overlooked because the clinical effect on birds can be subtle. In extreme cases, Aspergillosis will cause high and sustained mortality and there is usually no treatment for affected birds.
Q: How can producers ensure housing is up to scratch, in case of another AI housing order?
A: The Veterinary Health and Welfare Plans (VHWP) should serve as a dynamic document that provides detailed site-specific advice on how to navigate events such as housing orders.
Given the higher incidence of avian influenza (AI) over the last couple of winters, contingency planning should a site be involved in an AI case (be it an infected premises, within a control zone or as contact) is very sensible, and this can form part of the VHWP review. Irrelevant of whether a housing order is imposed, producers should ensure that housing is in good working order from a biosecurity and bird welfare point of view.
Some sites may even find it useful to have an external company visit and audit their set-up as well as making recommendations for any necessary improvements. This is often a more detailed process as it considers factors outside of the scope of the VHWP. Overtime, it is easy to become complacent and usually a ‘fresh pair of eyes’ is well-placed to advise on necessary improvements.