In farms, chickens are usually vaccinated against a variety of diseases including Marek's disease, Newcastle disease, infectious bronchitis, infectious laryngotracheitis, fowl pox, and fowl cholera. It’s a broad insurance that farmers take as they keep lots of chickens together in small spaces. If one chicken gets a disease, all the others would get infected pretty fast, and thus have a big economic impact. But what about vaccinations of our small backyard flocks?
What vaccines do chickens need?
Well, it depends very much to what viral diseases your chickens are exposed to. There are no regulations that require to vaccinate them for certain diseases.
It’s not necessary to vaccinate your chickens if they are not at risk of exposure to viruses. We (humans) don’t get typhoid, cholera, or yellow fever vaccines if we don’t travel to places where these diseases exist. Similarly, there is no point in introducing diseases in your flocks that your chickens will never encounter.
But since most viral diseases have no treatment, vaccination can help with the diseases to which your chickens are likely going to be exposed to. The most common viral disease in backyard flocks is Marek’s. And for chickens who are moved around (for example when exhibited at poultry shows), fowl pox and laryngotracheitis may be of concern as well.
When to vaccinate?
Newly hatched chicks have some passive immunity passed from the mother through the egg. So vaccinating chicks at less than 10 days of age doesn’t produce proper or long-term immunity. An exception is the vaccination for Marek's disease, which is ordinarily given on the day of hatch. Most hatcheries will vaccinate for an extra fee.
Do not vaccinate sick birds because their immune system is compromised and may not be able to withstand the stress of vaccination. The exception here is during the outbreaks of laryngotracheitis or fowl pox.
How to vaccinate?
Unless you have hundreds of birds to vaccinate, go to your vet. Most vaccines are developed, designed and packaged for commercial farms and come in vials for 1,000 or more birds. And vaccines containing live viruses are difficult to store properly.
Also the way to apply the vaccine depends of the vaccine itself, some are injected in muscles, others required stabbing the wing-web, while others are eyes or nose drops.
In short, get chickens who have been vaccinated for Marek’s. If you hatch them yourself, have a plan in place to vaccinate them on day 1.
And remember, vaccination is not a substitute for good biosecurity and sanitation practices. The best way to prevent viral diseases is to maintain a clean coop and disinfect everything coming in and out the chicken yard (cf. our biosecurity article).