They say that prevention is better than cure. Vaccines are used in health plans to train the immune system to deal with infection by building up an immune response. We routinely vaccinate ourselves, our cats, and our dogs. However, the advice isn’t as clear when it comes to our backyard flocks. The true answer depends on the size of a flock, location of your birds, and risk of those birds coming into contact with potential pathogens.

Size matters

In general, larger backyard flocks will be more difficult to keep completely isolated. This means that larger flocks tend to be more likely to contract a contagious illness. Additionally, the spread of infection will be accelerated when there are more birds in contact with each other. This makes a larger flock a better candidate when it comes to considering vaccine usage. One other thing to consider is that most vaccine vials come with a set number of doses. The minimum number of doses in a vial is usually 1000, so vaccinating a small flock will also end up with quite a bit of vaccine wastage.

location, location, location

When deciding whether to vaccinate your backyard flock or not, it is important to consider the location of your birds. Some parts of the country are at higher risk for certain illnesses because of the density of commercial farms in that area or the history of outbreaks in that location. You can check with your local veterinarian to see if they have specific recommendations for poultry vaccines for birds in your area.

One of the biggest factors that puts chickens at risk of catching a contagious illness is their contact with other birds outside the flock. There is always a risk involved when adding chickens to your site from outside sources. This risk can be minimized by imposing a quarantine on any new birds to the site. Fancy chickens are at risk every time they are brought to a show. It is close to impossible to keep them properly isolated in these conditions as they will likely share an airspace with the other birds present.

The Vaccines for Chickens

Once you have evaluated your chickens’ overall risk of infection, there are a number of specific vaccines to consider for backyard flocks. The following are a few pathogens (disease organisms) for which extra protection can be given through vaccines.  It is good to keep in mind that none will give 100% protection and even vaccinated birds can still acquire and shed the targeted microorganism. Your veterinarian can help you decide which ones would be most suitable for your flock.

Marek’s Disease

Marek’s Disease is a highly contagious virus that can cause neurological signs. Infected chickens may not show symptoms but will shed the virus which is transmissible through feather dander. This vaccine is generally recommended on sites with previous encounters of Marek’s Disease.


The coccidial organism is a gastrointestinal parasite, which causes damage to the gut of chickens. A backyard flock can typically be managed through proper site disinfection combined with regular testing and treatment. Commercial coccidial vaccines are available but are not generally not recommended for small backyard flocks.

Newcastle Disease

Newcastle disease is a virus which causes high mortality. It is commonly spread through contact with wild birds. Keeping excellent biosecurity is a huge contributor to protection of a flock. Commercial flocks are typically vaccinated for Newcastle Disease. Check with your veterinarian for recommendations in a smaller flock.

Respiratory Diseases: Infectious Bronchitis (IB), Avian Rhinotracheitis, and Mycoplasma Gallisepticum (MG)

Respiratory pathogens are readily transmitted between birds in shared airspaces. Serology testing can be done to see if there is a history infection on your site. These vaccines are typically recommended when there is evidence of previous infection or where large numbers of birds are being added to a flock.


This bacteria is known to cause disease in humans when transmitted from contaminated poultry products. The risk of contracting salmonella from your birds is very low as long as you observe proper hygiene when working with your birds and their eggs. The vaccine is typically only used in commercial settings.

Not sure what’s the best option? Find a local vet and look for “poultry” expertise in the dropdown!

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