April  2007

The “Waterfowl Flu Season” and Your Small Flock of Poultry

Being aware of the “flu season” for migratory waterfowl and shore birds can greatly cut the chances that your small flock of poultry will become infected with avian influenza. The number of avian influenza infected waterfowl increases dramatically during the fall when large numbers of young and mature ducks and geese mix together in staging areas. The number of birds infected and shedding the virus increases dramatically during the September to November time period. Due to cooler temperatures, the virus survives much longer in pond water and bird droppings in the fall compared to the summer. At 5ºC, the virus can last for weeks and below freezing it can survive until spring. Experience shows that this period of high virus shed and prolonged survival in the environment is the time of greatest risk of an outbreak of avian influenza in poultry. The risk is greatest for flocks that are house outdoors during this time.

Wild waterfowl and shore birds are a concern because they are the major reservoir of avian influenza. Wild ducks, geese and many shorebirds are well adapted to most strains of the virus and can appear very healthy even while shedding the virus in their droppings or into ponds and dugouts. Fortunately, many of the North American strains of the virus found in wild waterfowl and shore birds are not deadly for domestic poultry. The small number of strains with the potential to be deadly must infect thousands of chickens, turkeys or game birds to have the opportunity to change into a form capable of killing large numbers of poultry.

The Asian H5N1 strain of avian influenza is a unique strain of avian influenza that can be shed by waterfowl and shorebirds in the deadly form that is ready to immediately start killing large numbers of birds. While some wild waterfowl infected with the Asian H5N1 virus may appear sick, many will appear to be quite healthy. The Asian strain of avian influenza has spread to Russia, Europe, Africa and the Middle East but has not yet been identified in North America. 

Several Steps to Stop Avian Influenza from Jumping from Wild Waterfowl to Your Poultry Flock

1)      Market your meat-type chickens and turkeys before August 31^st and avoid the flu season in wild waterfowl. Your birds cannot be infected after they are in your freezer. If you get your chicks or poults at the start of May, it is easy for them to reach roaster weight by the middle of August. Consult the MAFRI website for guidelines on effective feeding of small poultry flocks:  http://www.gov.mb.ca/agriculture/livestock/poultry/bba04s00.html

2)      Housing your laying hens indoors from September 1^st until winter arrives will keep them more isolated from outdoor waterfowl during the high risk period.

3)      The spring migration is less risky than the fall migration but keeping your birds indoors until the end of May is helpful.

4)      Barns that house the flock should be big enough to hold both the type and amount of birds you have, year round if necessary.

5)      Avoid contact with waterfowl. Hunters must be especially careful and prevent any direct or indirect contact with your poultry.

6)      Follow the complete list of biosecurity guidelines in the factsheet, Small Flock Biosecurity.

While good biosecurity is a year-round practice, you should be especially vigilant during the fall waterfowl migration.

Carlyle Bennett, Terry Whitting and Glen Duizer
Manitoba Agriculture, Food and Rural Initiatives