Ozone Disinfection for Livestock Farms After a Flood: Restoring Poultry Houses, Pig Barns and Feed Stores Before the Next Batch Arrives

For poultry and pig farmers, a single flood can wipe out animals, feed, equipment and the income from an entire production cycle. What is often overlooked, though, is what the water leaves behind in the buildings once it has gone: mud mixed with manure, bacteria lodged in bedding and cracked floors, mould on walls, ceilings and evaporative cooling pads, and spores drifting through the feed store. If a new batch of animals goes in before those problems are dealt with, a second round of losses can follow. This guide is written for farm owners, farm managers and stockmen who want to restore their buildings step by step, and who want an honest picture of where ozone disinfection helps and where its limits are.

A Typical Scenario: A Sukhothai Broiler Farm and the Batch That Went Wrong

Somchai raises broilers in two closed evaporative-cooling houses in Sawankhalok, Sukhothai. In the year the Yom River burst its banks, water entered his houses faster than he expected. He had to catch and sell birds early and lost part of the flock. The water stood in the houses for almost a week, and in the feed room next door the bottom row of feed sacks was soaked. Once the water drained, Somchai shovelled out the litter and mud, hosed the floor, sprayed the disinfectant he had on hand and ran the tunnel fans at full power. He moved the upper sacks of feed, which looked dry, back into the store, because he wanted to restock as soon as possible.

When the new chicks arrived, problems appeared. Some birds were dull and off their feed, droppings were loose, and growth was behind the batch before the flood. The veterinarian who visited pointed to a combination of factors: moisture still trapped in the floor and walls, cooling pads caked with sediment and mould, drinker lines that had not been flushed internally since the flood, and feed kept in a damp room. When the sacks were opened, the feed inside had formed clumps with visible mould spots.

Somchai's conclusion was simple: a wash that looks good is not enough. Residual moisture, organisms hiding in dead spaces and contaminated feed can drag down the performance of a whole batch. This story is illustrative, but it reflects a pattern seen on farms across flood-prone areas, from Sukhothai, Ayutthaya and Ang Thong to Ubon Ratchathani, Pathum Thani and the low-lying south. The rest of this article works through each issue so that your recovery is complete.

What a Flood Leaves Inside Your Animal Houses

1. Bacteria from manure and wastewater

Floodwater on a farm is never clean. It carries manure, urine, rotting plant matter and community wastewater. Bacteria commonly found in animal intestines, such as Salmonella and E. coli, can lodge in mud, bedding, cracks in concrete, drainage channels and under slatted floors. Some affect animal health, causing diarrhoea, poor growth or illness, and some can also pass to people, which matters for everyone working on the farm.

2. Leptospirosis

After a flood, rats flee the water and move into animal houses and feed stores, where they find both food and shelter. Leptospira bacteria shed in the urine of rats and some other animals can contaminate water and damp soil. Pigs can be infected too, and farm workers who wade or clean without rubber boots and gloves risk infection through cuts or skin softened by long soaking. In people, the illness often starts with a sudden high fever, headache and muscle pain, especially in the calves. Anyone with these symptoms after wading through water should see a doctor straight away and mention the flood exposure. Thailand's Department of Disease Control repeats this warning every flood season.

3. Mould and mycotoxins in feed

Feed made from maize, soybean meal and grains is an excellent food source for mould. When sacks get wet or sit in a humid room, certain moulds can produce mycotoxins such as aflatoxin, which can weaken immunity, slow growth and reduce productivity. Critically, these toxins are invisible, do not always smell, and are not easily destroyed. Any feed that touched floodwater, became damp, or shows clumping or mould must be discarded. No method, including ozone, can make that feed safe again.

4. Mould on structures and cooling systems

Closed or evaporative-cooling houses have cooling pads, large fans, plastic curtains, ceilings and roof insulation. When these get wet or stay damp, they collect sediment and mould. Spores released from them are carried by the fans throughout the house, where animals breathe them every day. Poultry have respiratory systems that are sensitive to dust and spores, so breathing problems can develop more easily.

5. Ammonia and putrid odours

Manure that has fermented under water and soaked bedding release strong ammonia and rotten smells. These odours do not just bother workers; they can cause friction with neighbours, and at high levels ammonia irritates the airways of the animals too.

Who and what needs extra care

• Young stock, such as day-old chicks and piglets, whose immunity is still developing.
• Pregnant and lactating sows and breeder hens, where stress and environmental organisms affect both mother and offspring.
• Older workers or those with chronic conditions, such as diabetes, lung disease or allergies, who work in damp buildings.
• Children and pregnant women in families living near the houses, who should stay away from the area during clean-up.

The Burden Farm Owners Carry

Animal health and performance

Animals raised in an environment with accumulated organisms, high humidity and poor-quality feed tend to get sick more easily, eat less, grow more slowly and die at higher rates. Feed conversion suffers, target weights are missed and treatment costs can rise, adding further expense.

Costs and cash flow

The farm pays for discarded feed, repairs to fans, pumps, electrics and cooling pads, cleaning labour, and the lost income while houses stand empty. If the first batch after the flood also has problems, the financial burden compounds, and many farms end up borrowing more.

Lost time

Production cycles run on a tight schedule. A house that stays empty longer than planned, or has to be emptied again because the problem was not solved, pushes the whole year's plan back and may affect contracts with integrators or buyers.

Reputation with partners and the community

Contract farms usually have to pass a readiness check before receiving new stock. Clear cleaning and disinfection records make that inspection easier. Meanwhile, odours and flies that bother neighbours can become a source of conflict in the community.

Family

Many small and mid-sized farms have the owner's home and workers' housing on the same site. Damp, odours and mould from the animal houses and feed store affect the family's health directly, and debt stress affects everyone in the household.

Why Hosing and Spraying Alone Are Not Enough

Disinfectants lose power against mud and manure. Most disinfectants work poorly in the presence of organic matter. Sprayed onto a floor still coated with mud or manure, their effect drops sharply. That is why washing with detergent before disinfecting is essential.

Sprays do not reach every corner. Animal houses are full of dead spaces: behind cooling pads, above ceilings, inside roof structures, behind fans, inside feed troughs and in wall joints. Sprayers and pressure washers reach only part of them.

Fans dry, but they do not disinfect. Running fans at full power genuinely reduces humidity, but it also blows spores and contaminated dust through the house and out to neighbouring houses.

Lime or paint over mouldy walls without fixing the moisture just hides the problem under the surface, and the mould returns.

Odour neutralisers soften smells temporarily, but fermenting manure and bedding keep releasing gas.

The limits of ozone you should know. Equally, ozone is not the answer for every building. Ozone is a gas that needs an enclosed space to hold its concentration for the required time. Open-sided or mesh-walled houses are therefore not suitable for ozone treatment; for those, washing and farm disinfectants applied on your veterinarian's advice are the right approach. Spaces that do suit ozone include closed houses whose curtains and inlets can be sealed, feed stores, egg rooms, hatchery rooms, equipment rooms, worker shower and changing rooms, farm offices and staff housing.

Mapping Your Farm: Which Building Gets Which Treatment

Before anyone books a service, it helps to walk the farm with a notebook and sort every building into one of three groups. This simple map keeps the recovery honest and avoids spending money where it will not work.

• Enclosed spaces that suit ozone after washing and drying: closed evaporative-cooling houses whose curtains and inlets can be sealed, feed stores, egg rooms, hatchery and setter rooms, vaccine and equipment rooms, shower-in and changing rooms, the farm office, and staff or family housing that took on water.
• Open structures that need washing and farm disinfectant only: open-sided sheds, mesh-walled houses, loading ramps, manure sheds and outdoor yards. Here the key tools are removing organic matter, pressure washing with detergent, disinfectant chosen with your veterinarian, sunlight and time.
• Materials to discard or replace: wet feed, soaked bedding, crumbling cooling pads, waterlogged insulation, wooden feeders that cannot be cleaned, and any cardboard egg trays or packaging that touched the water.

Order matters too. Many farms work from the cleanest, most sensitive areas outward, for example the hatchery or egg room first, then the houses, then service areas, so that people and equipment do not carry contamination back into spaces already restored. Treat the staff shower and changing room early, because every worker passes through it before entering the houses. Finally, agree the downtime with your veterinarian before booking any contractor, so that ozone treatment slots into the empty period rather than delaying restocking.

The WHD Answer: Ozone Disinfection for Farm Buildings

World Health Disinfection provides residential and building ozone disinfection for homes, condos, hotels, offices, factories, schools and hospitals, including enclosed buildings on farm sites. Ozone (O3) breaks down the cell structures of viruses, bacteria and mould and breaks apart odour molecules, then reverts to oxygen (O2) with no chemical residue. That suits spaces where animals will later live and eat from troughs.

According to the test results certified for the company, WHD's service has been tested and certified by Thailand's Department of Medical Sciences and Intertek (UK) for eliminating viruses, bacteria and mould at 99.99%. Details are on the certification page.

How the work runs on a farm

1. Survey and suitability check. The team walks the site with the owner or stockman, identifies which houses and rooms can be sealed well enough for ozone, and plans the sequence around your biosecurity, for example moving from clean to dirty areas.
2. Post-wash readiness check. Bedding must be removed, mud washed out, surfaces cleaned with detergent and the building dried. If thick manure or mud remains, the team will ask for it to be dealt with first.
3. Preparation. All animals are removed; curtains, doors, inlets and fans are closed; systems that could draw ozone outside are switched off; the team confirms no people, animals or plants remain and posts no-entry signs.
4. Ozone release. The generator spreads gas throughout the space, including behind cooling pads, above ceilings and into hard-to-reach gaps.
5. Contact time. The concentration is held for the planned time, typically around 30 minutes per zone. Large houses may be split into several zones.
6. Rest and ventilation. Ozone reverts to oxygen and the space is ventilated before people re-enter, and before animals return according to the downtime your veterinarian sets.

Safety first: ozone treatment takes place only in an empty, closed space. Every animal, person and plant must be out, and nobody re-enters until the rest and ventilation period the team specifies has passed. Ozone is a step after mud removal, washing and drying. It does not replace cleaning, vaccination programmes, veterinary care or farm biosecurity, and it does not make wet feed usable. If animals fall sick or die unusually, contact your veterinarian or the district livestock office.

10 Reasons Farms Add Ozone as a Supporting Step After a Flood

1. No chemical residue in troughs or on equipment. Ozone reverts to oxygen, so returning animals do not contact chemical residue from this step. Learn more about ozone and chemical residue.
2. It reaches behind cooling pads, above ceilings and into roof spaces where spray nozzles cannot.
3. It deals with mould spores in an emptied feed store, reducing the chance that the next load of feed goes mouldy early.
4. It reduces ammonia and putrid odours trapped in the structure, making work easier and reducing complaints from neighbours.
5. It fits the downtime between batches, so it does not disrupt your production cycle.
6. About 30 minutes per zone, so you can plan house by house or room by room.
7. Referenced test results. According to the test results certified for the company, the service is certified by the Department of Medical Sciences and Intertek (UK) for 99.99% elimination of viruses, bacteria and mould.
8. It looks after the people's spaces too, including the farm office, changing rooms and flooded staff housing. See the ozone service page.
9. A clear work record supports your house-readiness file when integrators or inspectors visit.
10. A promotion for larger jobs. Ozone jobs of 15,000 baht or more receive a free medical-grade disinfectant spray for wiping high-touch points in offices and housing. Ask about the promotion.

Before and After: A House Ready for the Next Batch

Example Case: A Finishing Pig Farm in Ayutthaya

The following example case is an illustrative scenario reflecting common problems. It is not a review from any specific customer.

Wilai owns a mid-sized pig finishing farm in Bang Ban, Ayutthaya, with three closed houses, a feed store and staff housing. Floodwater covered the site for about two weeks. She managed to move most of the pigs to a relative's higher ground, but all the houses went under.

After the water receded, Wilai consulted the farm veterinarian before doing anything. The plan was to discard all feed in the store, remove manure and mud, pressure-wash floors and walls with detergent, scrub troughs, flush and dismantle drinker lines and nipples, remove damaged cooling pads for replacement, repair floor cracks and apply farm disinfectant as advised. The houses were then left to dry and rest for the period the vet specified.

During that downtime, Wilai booked WHD to ozone-treat each closed house in turn, the emptied feed store, the workers' changing room and the staff housing, which had a strong musty smell. Every step was done with no animals or people inside. Only after the rest and ventilation period did new feed go into the store and the next group of pigs arrive on schedule. Wilai says the most obvious change was the smell in the houses and the staff housing, along with having a complete record of every step to show her integrator during the readiness inspection.

Farm Recovery Checklist After a Flood

People's safety

• Cut the power before entering; have an electrician check fans, pumps and control panels before use.
• Wear rubber boots, rubber gloves, a mask and eye protection, cover cuts, and wash and shower after work.
• Anyone with fever, calf pain, diarrhoea or other symptoms after wading should see a doctor and mention the flood exposure.

Animals and carcasses

• Report sick animals or unusual deaths to your veterinarian or the district livestock office.
• Dispose of carcasses as the authorities advise, never into waterways.

Feed and water

• Discard feed that touched water, became damp, clumped or shows mould.
• Clean water tanks, drinker lines and nipples, and check water quality before animals drink.

Buildings

• Remove all bedding, manure and mud.
• Wash with detergent first, then apply farm disinfectant as your veterinarian advises.
• Inspect and replace damaged cooling pads, insulation and ceilings.
• Dry thoroughly and repair floor cracks.
• Plan rodent and fly control.

Ozone and aftercare

• Book WHD to treat enclosed spaces zone by zone with no animals, people or plants inside.
• After the rest and ventilation period, check everything before bringing in new feed and stock.
• Keep records of every step in your house-readiness file.

Frequently Asked Questions

Can we run ozone while animals are in the house?

Absolutely not. Ozone at disinfection concentrations is harmful to the respiratory systems of people and animals. It must be done only when the house is completely empty.

Can open-sided houses be treated with ozone?

They are not suitable, because the gas escapes before reaching the required concentration. Open houses should be washed and disinfected with farm products on veterinary advice, while ozone can still be used in the feed store, office and housing on the same farm.

If we dry wet feed and then ozone it, can we still use it?

No. Flood-soaked feed may carry pathogens and invisible mould toxins. Discard all of it for your animals' safety.

Can ozone replace the farm's disinfectant spraying?

No. Ozone is a supporting step after washing and disinfecting according to your farm programme. It helps with airborne organisms, odours and hard-to-reach dead spaces.

How long before we can restock?

After treatment, wait for the rest and ventilation period the team specifies before people re-enter. Restocking should follow the downtime set by your farm veterinarian.

Does WHD work outside Bangkok?

Contact the team by phone or LINE to check service areas and book a survey. They will assess the size of the job and recommend a plan that suits your farm.

Start the Next Batch in a House That Is Truly Ready

Talk to World Health Disinfection about ozone treatment for your closed houses, feed store and staff housing, carried out after washing and drying during the downtime between batches.

Book a Farm Ozone Survey

Call 065-556-6294 · LINE @whd268 · Email worldhealthdisinfection@gmail.com

Related services

• Ozone disinfection machines
• Disinfection service for businesses
• Contact World Health Disinfection

References

• Department of Disease Control, Ministry of Public Health (Thailand)
• CDC: Floods and Your Health