Canadian Poultry Magazine

Ask the Vet: Small flock disease risks

By Ben Schlegel   

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What threats does a surge in backyard chicken ownership pose to commercial farms?

Photo credit: © georgeclerk / Getty Images

One of the unanticipated outcomes of the COVID-19 pandemic has been a surge in interest among the general public in keeping small flocks of poultry.(1) Early on in the pandemic, bare shelves at grocery stores got people more interested in having their own sources of food close at hand.

As the pandemic has progressed, many people have found themselves stuck at home and looking to take on projects such as building a coop and caring for poultry. Sales of small flock chicks, feed and supplies have drastically increased.(2)

Innovation has proliferated in the sector, with services offering chicken “rentals”, including coops and supplies, all over North America.(3) This trend may help to bridge some of the gap in understanding between farmers and urbanites, when people who are several generations removed from the farm have to figure out how to handle poultry issues.


Small flocks are also becoming more common in rural areas, and some of them are close to commercial farms. While I think there are many positives to this boom in backyard birds for professional poultry producers, I also think it is critical that we are cautious of any disease risks that these new, small flocks may pose.

Poultry health concerns
Researchers working at the Ontario Veterinary College, University of Guelph, and Animal Health Lab in Guelph, Ont., recently finished a study on the health of backyard poultry in Ontario.(4,5) Bacteria that they found in backyard flocks included: Brachyspira spp., Mycoplasma synoviae, Campylobacter spp., Mycoplasma gallisepticum and Salmonella spp.

Viruses that they found in backyard flocks included: infectious bronchitis virus (IBV), fowl adenovirus, infectious laryngotracheitis virus (ILT), avian reovirus and infectious bursal disease virus (IBDV), as well as one case of low-pathogenic avian influenza and one case of Newcastle disease virus.

Birds from small flocks should never enter a commercial flock. Previous research has found that “bird movements are not likely to transmit disease from backyard to commercial flocks; however, human movements between backyard and commercial premises could transmit diseases.”(6)

Stay vigilant
Our industry needs to be vigilant for people introducing disease into commercial flocks from small flocks. It may be that employees and farm visitors have their own small flocks or recently visited one, particularly as they become more common, so it is critical that poultry producers ask people coming into their barns if they have had contact with small flock poultry.

Professional poultry producers always have biosecurity in mind when thinking about their operations. The National Avian On-Farm Biosecurity Standard from the Canadian Food Inspection Agency (CFIA) provides a great starting point for issues around poultry farm biosecurity. In order to limit the risk of introducing disease from a small flock to a commercial flock by staff or visitors, CFIA makes following recommendations:

“Recommendation 4: Each premises must have established procedures for employees entering a barn and moving to other barns within a premises. Employees should be trained and understand the reason behind and importance of these procedures. These procedures should include but not be limited to: Hand sanitation; not being in contact with other birds within a 24-hour period; and appropriate boot sanitation and change of clothing.”(7)

Additional considerations for personnel and visitors include:

“Ensure those who enter your premises are not sick, and have not been in contact with poultry, livestock, pets, and/or people that are sick, especially those exhibiting clinical signs related to influenza virus.

People who have had contact with poultry or poultry workers from other farm sites during the preceding 48 hours need to ensure they have washed (preferably showered) and changed into clean clothing before entering the RAZ where live poultry are kept.”(8)

I recommend a strict 24-hour downtime (at least) for anyone entering your barn from a small flock, with mandatory shower in, footwear change, hand-washing and farm-provided coveralls or clothing. Unfortunately, this means that farm staff cannot keep their own small flocks and look after commercial flocks.

For professional service people who understand biosecurity measures and have been on other commercial poultry operations with a high level of biosecurity, there may not be a need for the 24-hour downtime as long as the shower in, hand wash, footwear change and barn specific clothing procedures are met.

Make sure to ask any visitors with previous poultry exposure about the health status of the flocks they were visiting. For example, it may not be top of mind for tradespeople who had been in another poultry barn the day before on a different job. Ensure that any visitors to the barn (inspectors, auditors, service people, visitors) are made aware of these requirements before visiting the farm (or before they come into the barn if it is not possible to contact them beforehand).

Make sure to have locked doors to prevent farm visitors from entering the barn by mistake. If you are operating a poultry flock with an increased level of biosecurity (such as breeders), you may have to follow even more stringent guidelines than these suggestions with longer poultry-free downtime for visitors.

We know that pathogens of concern for commercial poultry production are circulating in small poultry flocks. Producers need to use biosecurity to avoid introducing these diseases to their flocks.


  1. “Worries about food shortages have people scratching for information on backyard chickens”. CBC News. April 18, 2020.
  2. “People are losing their clucking minds over backyard chickens”. Caroline Dohack. The HUSTLE. May 16, 2020.
  3. Rent the Chicken.
  4. A two-year prospective study of small poultry flocks in Ontario, Canada, part 1: prevalence of viral and bacterial pathogens. Brochu et al. Journal of Veterinary Diagnostic Investigation. 2019, Vol. 31(3) 327–335
  5. A two-year prospective study of small poultry flocks in Ontario, Canada, part 2: causes of morbidity and mortality. Brochu et al. Journal of Veterinary Diagnostic Investigation. 2019, Vol. 31(3) 336–342
  6. Preliminary Investigation of Bird and Human Movements and Disease-Management Practices in Noncommercial Poultry Flocks in Southwestern British Columbia. Burns et al. Avian Diseases, 55(3):350-357 (2011).
  7. National Avian On-Farm Biosecurity Standard – Second Edition. CFIA. 2018. P.18.
  8. General Producer Guide – National Avian On-Farm Biosecurity Standard. CFIA. 2014.

The primary author of this article is Ben Schlegel. The vets of Poultry Health Services are regular contributors to Ask the Vet. They work across the country from offices in Abbotsford, B.C., Airdrie, Alta., and Stratford, Ont. Please send questions for the Ask the Vet column to

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