Written by Alastair Chilcott
BVetMED MRCVS
Poultry Health Services at Mount Vets
Implementing effective biosecurity in free-range layer sites requires careful planning of site layout, traffic flow, and identifying critical control points.
Site layout and biosecurity zones
Sites should be designed with clear demarcations between general biosecurity zones (e.g., packing and egg storage rooms) and specific biosecurity zones (areas in direct contact with birds). Foot dips with DEFRAapproved disinfectants at appropriate concentrations should be placed at junctions between zones, covered, replenished weekly, and used only with clean boots. However, as maintaining clean boots is challenging, having specific biosecurity-zone boots for staff and visitors is advisable.
Visitor and staff protocols
All visitors and staff must sign in and out, detailing previous farm visits for traceability. PPE, including coveralls, gloves, and boots, should be available for all personnel. Staff should not keep poultry at home, and other animals like cats and dogs should be kept offsite. Visits should be arranged from younger to older birds and from ‘clean’ to ‘dirty’ sites to minimize disease transmission risk. Between sheds, hands should be washed, and coveralls and boots changed.
Vehicle management
Vehicles must be washed and disinfected upon entry and parked outside the general biosecurity zone. Only essential vehicles such as feed lorries, which should be clean and disinfected on-arrival, should enter the site. Eggs and dead birds should be stored in a central location, ideally off-site, to reduce vehicle traffic in biosecurity zones.
Feed and water hygiene
Feed bins must be kept dry to prevent mould and mycotoxin formation.
Maintaining drinking water hygiene is crucial for bird health and treatment efficacy. Water lines should be flushed and cleaned between flocks and during the flock lifecycle to prevent biofilm build-up, using hydrogen peroxide or chlorine-based sanitisers.
Cleaning and disinfection
Post-depletion cleaning is vital to
prevent disease spread to new flocks.
Sheds should be thoroughly washed,
soaked with detergent, dried, and
disinfected. Leaving sheds empty for
at least 14 days can further reduce
pathogens. Insecticides should be
applied as soon as possible after
depletion to be effective.
Equipment must be cleaned,
disinfected, and kept shed-specific;
if this is not possible for specific items,
they should be disposed of and replaced
before the new incoming flock.
Management of sick and dead birds
Sick birds should be isolated in separate hospital pens. Dead birds must be removed as soon as possible and stored in refrigerated facilities to prevent disease spread. Prompt removal of carcasses is essential to minimize pecking and disease transmission.
Rodent and insect control
Rodents transmit diseases and cause damage, making vigilance essential. Use traps, bait boxes, and vermin control specialists to minimize rodent numbers. Measures include sealing holes, removing feed/manure residues, and maintaining short grass. Insects like darkling beetles, red mites, and flies also transmit diseases. Keeping manure dry (>45% dry matter), using fly screens, and traps can help control insect populations.
Wild birds and environmental risks
Wild birds should be discouraged by removing spilled feed, covering air inlets with mesh, and avoiding standing water on the range. Proximity to other poultry farms and bodies of water where waterfowl are present poses biosecurity risks, as diseases can spread via airborne particles.
Summary of critical control points
Free-range poultry sites can enhance biosecurity by focusing on:
- Boundaries between biosecurity zones
- Management of staff and visitors
- Control of vehicle movement
- Proper feed and water hygiene
- Thorough cleaning and disinfection between flocks
- Handling of sick and dead birds
- Control of pests and insects
- Mitigation of risks from proximity to other poultry sites
By adhering to these guidelines, freerange poultry units can significantly reduce the risk of disease outbreaks and maintain healthier flocks.