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Reducing salmonella risk in table egg production

Quick facts

  • Purchase chicks from hatcheries in the United States Sanitation Monitored program and pullets from sources with salmonella prevention and control programs.

  • Control rodents, insects and wild birds on your farm.

  • Clean, wash and disinfectant poultry houses between flocks.

  • Monitor bacteria on your farm through laboratory testing.

  • Attend to feed quality control and proper feed storage.

  • Properly wash and store eggs to prevent salmonella contamination.

  • Have a strong and strict biosecurity program for your farm.

Chick and pullet replacements

Chickens are very prone to salmonellosis at two ages.

  • 1 to 14 days of age

  • When pullets move to laying houses

Optimal nutrition and care can help keep your birds healthy and reduce the risk of salmonella at these ages.

  • Purchase your chicks from hatcheries taking part in the United States Sanitation Monitored program. Get your pullets from sources with good salmonella prevention and control program.

  • Have a reputable hauler for your pullets. Make sure the pullets travel in clean coops and trucks. Undisinfected coops commonly carry salmonella.


Bacterin can stop vertical transmission of salmonella in turkeys. Salmonella vaccination research is underway at the Universities of Maine and Minnesota and other places. Early signs suggest that bacterins also reduces the spread of salmonella in chickens via feces and eggs.

Some companies produce bacterin for commercial use.

Controlling rodents, insects and wild birds

Vectors are organisms that can spread disease. Vector control throughout your flock’s life is key to reducing salmonella.

  • Work routinely with a licensed professional rodent and insect exterminator.

  • Be sure that personnel practice strict biosecurity steps for their clothing, equipment and vehicles.

  • Make sure service providers have a good vector control record with poultry operations.


Rodent feces can contain infectious amounts of salmonella. Mouse feces, common in feed troughs, may amplify salmonella disease in poultry. Rodents also carry disease to near and distant houses and farms.



Using several practices to control insects reduces the chance of insects adapting to a single method.

For example

  • Keep manure well ventilated and dry.

  • Prevent water leaks and remove wet areas.

  • If possible, use biological control methods (fly parasites and predators).

  • Use different types of insecticides.

Applying insecticide

  1. Clean and disinfect the poultry house floor.

  2. Once the floor dries, apply an approved insecticide to the floor, support poles and walls.

  3. Always follow the manufacturer’s safety precautions.

You can use synergized pyrethrins (pyrethrin plus piperonyl butoxide) in automatic spray systems inside poultry houses. These quickly knockdown flying insects, have short residual times and have low toxicity in mammals. Don’t apply these insecticides more than twice weekly, especially if you use a spray system.

Wild birds and pets

  • Avoid feed spills outside the buildings and clean up any spills right away.

  • Buildings should keep out wild birds and prevent them from sitting under eaves or on blinds.

  • Keep pets out of pullet and layer houses.

Cleaning facilities

Always clean pullet and layer houses between flocks to reduce possible buildup of disease agents, such as salmonella.

Clean facilities as soon as you remove the birds if any tested positive for salmonella. Cleaning will prevent replacements from contamination.

Good cleaning programs need to:

  • Be put in place across the entire farm

  • Have proper equipment

  • Have professional training

Cleaning conventional facilities presents a big challenge due to the following.

  • Facility size and complexity

  • Wooden construction materials are harder to disinfect than smooth metal surfaces

  • Plastic and fibrous egg handling surfaces are harder to disinfect than smooth metal surfaces

These problems decrease how effective cleaning plans are. In the past, many used formaldehyde to help disinfect porous surfaces. Although effective against salmonella, its use comes with human safety concerns, poor product availability and regulatory policies. Other options may help disinfect porous surfaces.

  • Other fumigants

  • Heat-enhanced disinfectants

  • High-pressure sprays or disinfectant foams

  • Sealants to reduce the rough surface of wood

Step-by-step cleaning


Preparations for restarting

  1. Replace disposable items with new ones (for example, sponges on egg conveyor equipment).

  2. Repair and adjust your egg handling and conveyance system from hen to cooler.

  3. Remove old water filters. Clean and disinfect casing and install new filters.

  4. Restock restrooms and portable toilets with soap and paper towels.

  5. Make sure that all electrical equipment work properly.

  6. Clean all equipment used for washing and disinfecting the facility and store them in a clean, secure space.

Monitoring bacteria

You must monitor bacteria through laboratory testing to complete your quality control program. Monitoring helps keep track of how well you’re reducing risk. Lawyers suggest that knowledge of a problem is better than none.

Collecting samples

Sampling often requires on-the-spot judgements. How you collect samples is more important than how many you collect. Poor sampling or laboratory methods can result in a false negative reading. Choose a laboratory that follows good salmonella culture methods.


Monitoring plans and schedules

State laws, regulations and policies differ on the privacy of voluntary monitoring to help gain research, disease and in-house quality control data. Positive results during any bacteria monitoring times (see table 1) may present complex fiscal, legal and ethical issues. The same may be true for if you don’t monitor. Work with professionals (legal, underwriter and veterinary) to develop monitoring programs and choose from the following examples for pullet and layer flocks.


Egg handling


Feed and water

Many salmonella types have been found in feed and feed ingredients. You must prevent salmonella contamination after manufacturing. Take care in selecting feed suppliers and in shipping and storing feed.



Biosecurity practices that prevent most diseases are equally good within a salmonella risk reduction program. Salmonella infects flocks when a virus or disease agent weakens your flock’s natural defense. Thus every step in biosecurity is an investment in flock survival.

People can also aid in spreading salmonella to chickens and eggs. Thus, all farm workers must have good hygiene. Provide clean, working toilets with hand washing and drying facilities to serve all employees.

Provide training materials such as videos or pamphlets to employees at all levels. Review such materials regularly and add practices as you see fit for your farm.

Biosecurity checklists

Checklists for flock caretakers and farm managers

Flock caretakers

You can post this list in all poultry houses. Consider printing large, clear posters.

  • Watch for, correct and report right away any rodent, insect, wild bird or pet problems.

    • Rats and mice are especially important!

  • Check daily for quick, secure removal of all dead and dying birds.

  • Have disinfectant soap available for personnel handling chickens or eggs.

  • Don’t go into the poultry house after hunting.

  • Keep egg belts, elevators, etc. in proper adjustment. Regularly clean and sanitize.

  • Wear clean clothing.

Farm managers
  • State in contracts and check that all pullet deliveries are made in clean and disinfected coops and trucks.

  • Make sure all visitors, farm executives and others wear biosecure clothing.

  • Ban caretakers from having any poultry flocks at home.

Spent hen removal

  • Make sure all racks are clean before they enter the poultry house.

  • Be sure the driver dresses in clean clothing before going into the poultry house.

David Halvorson, emeritus professor, College of Veterinary Medicine

Reviewed in 2018

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