The main purpose of work during the downtime period at a breeder farm is to clean, disinfect, and maintain the environment and equipment inside and outside the poultry house, thereby removing pathogenic microorganisms from the house and equipment, breaking the transmission chains of various pathogens, ensuring that the previous flock does not affect the health or production performance of the next flock, and keeping the equipment operating normally.
Cleaning, washing, and disinfecting poultry houses is a complex, systematic task. A scientific and reasonable cleaning, washing, and disinfection procedure should be established before the breeder flock is depopulated. The entire process should be arranged scientifically and reasonably according to the time available, the number of personnel, and the characteristics of the tools. Therefore, inspectors should consider inspection points from different perspectives.
1 Monitoring the cleaning and washing of poultry houses and equipment
1.1 Monitoring the removal of equipment
All movable equipment and facilities, such as drinkers, feed troughs, feed bins, detachable feed lines, egg-laying nests, partition doors, partition nets, heating equipment, and various tools, should be removed from the poultry house and placed on the concrete surface outside. Equipment in the poultry house that is not suitable for moving must absolutely not be moved outside. Any unused medicines remaining in the poultry house should also be collected, returned to storage, and fumigated for disinfection.
Remove or protect items that should not or cannot be washed and disinfected, such as thermostats, thermometers, voltage regulators, fan motors, manure-scraper motors, light bulbs, medication dispensers, spray-line nozzles, and distribution boards. Designated personnel should handle dust removal, maintenance, washing protection, and fumigation disinfection, and place these items in the designated storage room for isolated storage.
1.2 Control of cleaning in the poultry house, equipment, dust, and manure: All dust, debris, and cobwebs must be swept from raised areas and corners throughout the poultry house, preferably with a broom or blower.
Remove all manure, litter, debris, and leftover feed in feeders from the poultry house and move them to the manure storage area, protecting them to prevent contamination of the site. After each poultry house is cleaned, assign personnel to scrape manure accumulated on slats, cages, corners of the house, and other surfaces, and carefully sweep up all remaining chicken manure in that house. All manure and litter in the manure storage area must be removed before washing.
1.3 Control of washing
First, switch off all electrical equipment in the poultry house. Use a high-pressure washer for a preliminary rinse to soak the dust and debris remaining on the poultry house and equipment. After soaking, wash with a high-pressure washer. During washing, quickly drain any water remaining in the poultry house. Pay particular attention to washing the following parts of the poultry house: the tops of roof beams, walls, the inner and outer walls of the manure pit, the floor of the manure pit, slats, heating equipment, drains and drain openings, fan frames, louvers, fan shafts, fan blades, various supports, water pipes, and spray pipes.
Equipment moved outside the poultry house must also be soaked and washed. Equipment that cannot be washed may be wiped and disinfected. After the equipment has been thoroughly washed, store it under cover whenever possible.
The outside of the poultry house must also be washed thoroughly. Pay attention to washing the following areas: air inlets, heater rooms, workrooms, feed rooms, drainage ditches, and concrete roads.
The washing standard for the site's manure storage area must be the same as for the poultry house. Cleaning auxiliary facilities: All auxiliary facilities on the site, such as offices, dining rooms, kitchens, dormitories, laundry rooms, bathrooms, toilets, egg rooms, feed stores, boiler rooms, carports, fumigation rooms, and fumigation chambers, must be thoroughly washed. Floor drains, settling tanks, and similar areas in each location must also be cleaned.
The quality of poultry house cleaning and washing directly affects the quality of disinfection. Inspectors should examine everything carefully and thoroughly, without overlooking any detail or anything suspicious (a handheld light may be used during inspection inside the poultry house).
2 Disinfection of chicken houses and equipment, and overall biosecurity control of the site
2.1 Disinfection process control
The type and dosage of disinfectant should be selected according to the product instructions. Disinfection should be carried out correctly and records kept. Throughout the disinfection process, equipment should be protected as appropriate based on the properties of the disinfectant to avoid damage to the equipment.
Reference disinfection procedure: First spray the rinsed chicken house with 2%–3% caustic soda solution —> air-dry —> rinse with clean water —> alternate spraying commonly used disinfectants, with an interval of 1–2d between applications; spray the next disinfectant only after the previous one has dried —> after sealing the house, spray with 10% formaldehyde solution for disinfection (temperature maintained above 15℃, 24~48h) —> fumigate with a smoke fumigant for 24-48h. The entire disinfection procedure takes approximately 10–12d.
Note: Disinfection should only be carried out after the entire chicken house has been thoroughly rinsed and repairs have been completed. Disinfectants are ineffective against dirt and organic matter. Check that the chicken house is properly sealed and that the ancillary facilities on the site have been disinfected as required.
2.2 Control of overall biosecurity procedures on the site: Verify that incoming vehicles, personnel, and materials have completed all required disinfection procedures before entering the site, and that records are kept; ensure that all cleaning, renovations, and disinfection on the site follow strict biosecurity protocols to prevent cross-contamination between clean and contaminated areas; verify that insect, rodent, and wild bird control measures have been carried out, with records kept; check that protective screens on all air inlets and outlets have been repaired and that all doors and windows can be closed tightly.
Note: Insects are important disease vectors and must be killed before they migrate to wooden items or other objects. After the breeding chickens have been culled, while the chicken house is still relatively warm, insecticide should be sprayed immediately on the litter, chicken house equipment, and the surfaces of the chicken house walls. The insecticide should be applied a second time before fumigation disinfection.
3 Control of maintenance conditions for the site, chicken houses, and equipment
3.1 Renovation and repair of the farm site and poultry houses
A clean farm site and empty poultry houses provide an ideal opportunity for site renovation and repairs to building structures. Once the site is vacant, renovations and repairs should be carried out promptly based on problems caused by improper practices during the previous flock cycle.
Pay attention to the following: whether the site renovation projects are appropriate and meet all site operating requirements, such as biosecurity requirements; when renovating poultry houses, also ensure that sealing repairs are carried out, such as using concrete or cement to fill cracks in the floor, repairing wall joints and the cement render, repairing or replacing damaged walls and roofs, and ensuring that all poultry house doors close tightly.
3.2 Equipment installation and commissioning
Install and commission equipment and other items that were dismantled for washing or are used for short periods, such as thermostats, voltage regulators, fans, motors, light bulbs, medication dosers, and brooding hoods. Carefully check whether all equipment has been maintained, serviced, and thoroughly disinfected, whether it has been installed correctly, and whether the quantities are accurate.
4 Control of supplies and environment before chick placement
4.1 Preparation of poultry house supplies: All supplies should be prepared in advance before chick placement, such as water, feed, medicines, and other auxiliary tools.
4.2 Preparation of the poultry house environment
To achieve the appropriate temperature, humidity, and lighting for the chicks, the site must be preheated. For example, in a brooding house, the house temperature must reach 26~28℃ 2~3d before chicks arrive (in winter, 5~7d beforehand), the brooding umbrella must be switched on, the litter temperature beneath the umbrella must rise to 30~50℃, the litter temperature at the edge of the enclosure must be 26~28℃, and humidity must be above 70%; the temperature for growing chickens should reach 18~24℃, with humidity at 50%~65%.
5 Evaluation of washing and disinfection effectiveness
To assess the effectiveness of poultry-house washing and disinfection, use the total bacterial count. This will help improve hygiene at the poultry farm and compare the effectiveness of different washing and disinfection procedures. After effective disinfection at the poultry farm, none of the opportunistic pathogens should be isolated during testing.
Reference criteria for evaluating disinfection effectiveness in an empty house: After disinfection, place several exposed agar plates at the four corners and center of the poultry house for 10 min. Use a sterile cotton swab to sample equipment surfaces and streak the samples onto agar plates. Incubate for 24 h, count the colonies, and calculate the average.
Provisional standards for water samples: The bacterial content of the water must not exceed 100 per mL, and the Escherichia coli content must not exceed 3 per L.
Finally, based on the inspection and bacterial test results, complete the standard form and assign a score to provide an overall evaluation of procedures during the empty-house period.
6 Actions when disinfection effectiveness does not meet the standard
When test results indicate contamination at or above the mild level, take appropriate action before the chickens arrive. If there is sufficient time before the chickens arrive, repeat fumigation disinfection and collect samples for testing. If time is limited, to reduce the effects of fumigation gases on the chicks, spray with a disinfectant solution with a mild odor as a remedial measure.
If water quality testing shows that the required standards have not been met, take appropriate disinfection measures or increase the dosage of the existing disinfectant. In the few days before the chicks arrive, suitably warm boiled water may also be used to reduce stress. After taking the appropriate measures, collect samples promptly for testing to confirm their effectiveness.