Storey's Guide to Raising Chickens (44 page)

A vaccine has been created to protect chickens against the known high-path strains, for use only in the event of an outbreak to create a buffer zone around
diseased flocks and prevent spreading of the flu while infected chickens are being destroyed. But bird flu viruses frequently mutate, just like the human flu viruses. And just as your flu shot doesn’t always give you immunity against the flu strain that’s going around, existing bird flu vaccines may not protect chickens against future bird flu strains.

Are your chickens likely to get bird flu? Probably not. The most common way avian flu spreads from chicken to chicken is through direct contact with droppings from infected birds and droppings on contaminated equipment and shoes. Avian influenza is more likely to occur in industrialized factory farms where thousands of chickens are irresponsibly crowded into unsanitary environments than in a small flock enjoying the benefits of sunshine and fresh air.

Are you likely to get bird flu? Probably not. Even if the virus appears again among factory-farmed chickens in this country, it does not readily mutate into a form that spreads from human to human.

Some diseases may be effectively treated if you catch them in the early stages and make a positive identification so you’ll know precisely what treatment to use. A few illnesses have characteristic signs. With a little knowledge you can easily identify these diseases yourself. Many diseases, however, have such similar signs that the only way you can get a positive identification, or diagnosis, is by taking a few dead or sick birds to a pathology laboratory for analysis. The path lab won’t tell you how to treat the disease, though. For information on treatment, you’ll have to take the path report to your regular vet or to your state Extension poultry veterinarian or Extension poultry specialist.

Develop a policy in advance for dealing with disease outbreak. That way, if you ever have an illness in your flock, you’ll be ready to act quickly. The moment you suspect a chicken is sick, isolate it from the rest of the flock; then make a choice: either humanely kill the bird and dispose of the body according to local health regulations (burn or deeply bury are two options), or try to find out what’s ailing it and begin active treatment. Before any problems occur and while you are unemotional, determine in advance exactly how much time and money you are willing to spend nursing sick chickens.

When you are developing your disease-response plan, keep in mind that avoiding diseases is usually more effective and less frustrating than treating diseases, for these reasons:

By the time you notice a chicken is sick, chances are it’s too far gone to be treated effectively.

Keeping an unhealthy bird carries the risk that the afflicting disease will spread to others in your flock.

Chickens that survive a disease rarely reach their highest potential as layers, breeders, or show birds.

A chicken that gets a disease, even if it fully recovers, will pass its lack of resistance to its offspring.

A chicken that fully recovers may become a carrier, continuing to spread the disease without showing signs.

Some diseases are so serious the only way to stop them is to dispose of the entire flock and start over.

Vaccination is a measure you may or may not need. Newly hatched chicks acquire a certain amount of natural immunity from the hen via the egg and continue to acquire new immunities as they grow to maturity. Your chickens may need additional help to develop immunities against diseases commonly encountered in their environment.

Ask your veterinarian or state Extension poultry specialist to help you work out a vaccination program based on diseases occurring in your area. Vaccinate your flock only against diseases your birds have a reasonable risk of getting, including past diseases chickens have experienced on your place or new diseases that pose a serious threat in your area. Do not vaccinate against diseases that do not endanger your flock.

The most common diseases for which vaccines are given to small flocks are listed below. They are all viral diseases.

Fowl pox,
unrelated to chicken pox in humans, causes scabby skin, fever, and loss of appetite. It is spread by blood-sucking insects and through injuries resulting from peck-order fighting. This vaccine should be used only if your flock, or your area, has a problem and then all your chickens must be vaccinated and yearly booster shots given.

Infectious bronchitis
is one of several viruses that cause coldlike signs, including coughing, runny nose, and swollen eyes. It is so contagious it can spread through the air from one chicken to another 1,000 yards (915 m) away. The signs are similar to Newcastle disease, and the two vaccines are often combined.

Laryngotracheitis
is often spread at poultry shows and causes chickens to cough and gasp. It is similar to infectious bronchitis but spreads less readily and is more severe. The vaccine should be used only if your flock, or your area, has a problem. It may be used to prevent the spread of infection, but once you use it you must vaccinate all your chickens now and in the future and give yearly booster shots.

Marek’s disease
causes leg paralysis and droopy wings and sometimes death. Chickens with this disease shed the virus whether or not they show signs and thereby contaminate the yard for all future chickens. Vaccination does not prevent chickens from becoming infected and shedding the virus, but it does prevent paralysis. Chicks must be vaccinated before being exposed to the virus, and therefore most hatcheries offer to vaccinate chicks before shipping them.

Newcastle disease
is brought into the United States by illegally imported birds and spread through droppings on used equipment and on people’s shoes. It is easily confused with other respiratory infections. A combination vaccine is available to prevent both Newcastle and infectious bronchitis.

If you wish to administer two or more vaccines that don’t normally come in combination, check with the supplier or a veterinarian to determine if the two are compatible. Some vaccines interfere with the effectiveness of others when used at the same time.

Acquiring chickens from different sources and at different times, as well as taking chickens to shows and bringing them back home, increases their risk of getting a disease and spreading it to your other chickens. Because some diseases are easily transmitted from bird to bird, and because recovered birds may become carriers that transmit the disease without showing signs of illness, some states require exhibitors to vaccinate against certain diseases. Before you decide to show your chickens, find out what the local regulations are and determine if you feel comfortable complying.

A vaccine confers immunity only if it is fresh, has been stored and handled properly, and is given exactly as directed on the label. A vaccine transported in a cooler and administered properly should work. A vaccine left in a hot car all day likely won’t work no matter how well it’s administered. The chickens also must be receptive to being immunized, which they will be if the weather is temperate
and the chickens are properly fed and housed, have no internal parasites, and are otherwise in top health.

SAMPLE VACCINATION SCHEDULE*