An outbreak of avian influenza, Newcastle disease or any other number of diseases has the potential to devastate the poultry industry. According to Dr Margaret MacKenzie from Inghams, an outbreak of avian influenza in a clustered chicken meat farming region could potentially wipe out the industry in that state. This is a rather sobering message.

In recent years, we have experienced a trend of increased outbreaks of avian influenza associated with free-range poultry, turkeys, layers and ducks. To date, these have been relatively isolated occurrences, readily controlled and eradicated, but still of significant cost to both industry and government. Such a trend cannot be sustained.

A similar outbreak in a clustered intensive meat poultry production area would have severe economic, consumer and regulatory consequences for the entire poultry industry.

What can free range growers do to manage this risk?

The good news is that an effective and implemented biosecurity plan for free-range flocks will significantly reduce the risk of an exotic disease outbreak. There is a common misconception that free range farms are by nature poor biosecurity enterprises. In fact, most biosecurity principles can be effectively implemented to both closed shed as well as open free-range systems.

However the unique and specific challenges posed by free-range production must be addressed, to ensure the continued growth and viability of the industry.

These include shedding and personnel standards, vermin control, dead bird and waste disposal, feed management, water quality, exclusion of wild and domestic animals and equipment, vehicle and shed hygiene procedures.

Free-range birds have access to an outdoor range and are potentially exposed to additional biosecurity risks and diseases, the most significant being wild birds, rodents, wild animals and airborne transmission of infectious agents.

As a result, diseases such as avian influenza, infectious laryngotracheitis, histomoniasis, helminths, coccidiosis and food safety pathogens such as Salmonella and Campylobacter may occur at a higher frequency in poorly-managed free range poultry farms.

All of these are controllable with effective range biosecurity.

The most significant biosecurity risks in a free-range operation are:

• wild birds
• rodents
• wild animals
• airborne infection

Tips to protect your free-range farm from disease

Range management

1. Maintain the range in a clean and tidy condition.
   
   
2. Grass should be kept short, as long grass attracts wild birds and rodents onto the range, and favours the survival of viruses and bacteria.
   
   
3. Do not plant vegetation on the range which attracts wild birds. For example, avoid fruit bearing trees and shrubs. Consult a horticulturalist for assistance.
   
   
4. The best shade structures are sails and shade-cloth as these tend to scare away wild birds when they flap in the wind.
   
   
5. Do not provide feed on the range as this attracts birds and rodents. Always clean up feed spills around silos immediately. Isolate silos from range areas.
   
   
6. No visitors should be allowed access to the range area.
   
   
7. Keep ranges free of surface water including pools, puddles, dams and waterways.
   
   
8. The range must be well-drained. Do not allow free-standing water to collect. Water for range irrigation must be treated to drinking water standard.
   
   
9. There must be secure fencing of the range to prevent access to domestic animals, including dogs and cats and wild animals such as foxes, wallabies and wombats etc. Many wild animals carry Salmonella and Caampylobacter.
   
   
10. Secured rodent baiting stations should be placed at 10-metre intervals around the range perimeter fence and around the shed. Baits should be checked weekly and replaced every two to four weeks, depending on vermin activity patterns. Make sure the baits you select are approved for outdoor use.

Airborne transmission

11. New free-range farms should be sited away from other poultry enterprises, preferably in low-density poultry farming areas
    
    
12. Strategic planting of trees and large shrubs can be used to filter and block airborne spread. Try to avoid trees which are attractive to wild birds

Wild birds (particularly waterfowl)

Wild birds represent the most serious disease risk to the free-range poultry industry, and water attracts birds and animals to the range areas.

13. There should preferably be no dams, waterways, rivers or lakes in the vicinity of free range sheds
    
    
14. New farms should be located away from dams, rivers, lakes etc.
    
    
15. Remove or drain non-essential dams and other water sources
    
    
16. Install bird scaring systems, e.g. auditory, visual deterrents
    
    
17. Shade sails act as a deterrent to wild birds on the range
    
    
18. Waterfowl MUST NOT have access to your flock’s drinking water, for example water storage tanks.

A risk assessment should be conducted to determine the level of risk a particular farm has to exposure to wild birds and other sources of disease. High-risk farms are those that are:

• in or close to a cluster of intensive poultry growing farms
  
  
• in the vicinity of a dam, river, lake or other body of water. Generally farms within 3km of a water body which is frequented by large numbers of waterfowl would be considered a higher risk.
  
  
• If free-range farms are in an area of intensive poultry population, and waterfowl are identified as having access to the range, the range should be netted.

For new free-range farms:

19. Site the farm away from intensive shedded poultry populations
    
    
20. New farms should preferably not be built in the vicinity of dams, lakes, rivers or other water-bodies. If waterfowl habitat is within one kilometre of the free range farm, the range should be netted.

Summary

• Good biosecurity practices can be just as effective on free range farms as they are in intensive poultry farming systems
  
  
• You can protect your farm and your industry by adopting pretty simple yet effective strategies to prevent disease from entering your farm
  
  
• In addition to the ‘National Biosecurity Manual for Chicken Growers’ and the NSW biosecurity guidelines for free range poultry farms, free range farmers should adopt the 20 guidelines listed in this article to manage and prevent the additional biosecurity risks associated with free range systems.

Adapted from 'Range management for disease control' by Dr Margaret MacKenzie of Inghams Enterprises, presented at PIX in May 2014.

October 2014