| Disease | Occurrence in Backyard Flocks | Distinctive Signs of Illness | Average Mortality Rate |
|---|---|---|---|
| Mycoplasmosis | Common | Foamy eye discharge, more common in winter, roosters usually show more severe signs | Usually none |
| Infectious coryza | Common | Swollen face or wattles, gunky eyes, foul odor, more common summer and fall | 5–20 percent |
| Infectious bronchitis | Common | Decreased egg production | Usually none |
| Newcastle disease | Mild strains are common. Highly deadly strains are absent from chickens in the United States. | May also cause diarrhea, staggering, paralysis, sudden death | 5–99 percent |
| Fowl cholera (chronic form) | Not so common | Swollen face, gunky eyes, rattling or difficulty breathing, more common in late summer | 0–20 percent |
| Infectious laryngotracheitis (ILT) | Not so common | Gasping, coughing up bloody mucous, dried blood around nostrils and lower beak | 10–20 percent |
| Avian influenza | Rare (Deadly strains are absent from chickens in the United States) | Droopy birds, rattling breathing sounds, diarrhea, sudden death | 5–99 percent |
Sometimes a chicken’s face will swell, especially around the eyes, cheeks, or wattles. The comb may turn a bluish color. The disease’s severity depends on the organism strain and on the flock’s overall health at the time the disease strikes.
Chicken respiratory infections are usually spread by direct contact between infected and uninfected chickens, but stuff that infected chickens have sneezed or coughed on, such as transport coops or clothing, can carry the infectious organisms from place to place, too. An infected hen can transmit mycoplasmosis through her eggs to her chicks.
Preventing respiratory illness from invading your flock and having a major impact is a matter of good biosecurity and flock management. Attention to biosecurity (things you do routinely to keep infectious diseases out of your flock) can help you avoid bringing respiratory infections home to your chickens. If an infection should happen to get through your defenses, a clean, comfortable, and well-fed flock is less likely to experience severe disease.
Diagnose chicken respiratory illness
You can guess, but you won’t be able to tell for certain which disease is causing your chickens’ woes, unless you have laboratory tests performed. Veterinary diagnostic laboratories and veterinarians who treat poultry can help you.Although diagnostic tests will cost you some money, getting to the bottom of the problem may be worth the expense, because a diagnosis allows you to
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Know whether your birds are likely to be contagious and spread the infection to other birds. This concern is especially important if you breed and sell birds or take birds to shows. Chickens can recover from infections and appear healthy, but carry and spread the disease to other chickens, possibly for the rest of their lives.
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Choose a medication that is likely to work. Antibiotics are helpful to control the signs of some infections, but not others. Certain antibiotics kill certain organisms, but have no effect on others. If you get a diagnosis, you’ll be able to use the appropriate drug; if not, you may have to play antibiotic roulette and hope you’ve picked the right one — or spin again.
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Know whether a vaccine can help you control the problem. Vaccines are available that help control several respiratory infections, including infectious coryza, mycoplasmosis, and infectious laryngotracheitis.
Getting a diagnosis may bring more attention to your flock than you expected. In the United States, some or all the diseases listed in the preceding table are reportable in most states, meaning that laboratories and veterinarians are required by law to report the presence of the disease in your flock to the state veterinarian’s office.
What officials do with the report varies from state to state. In some places, your flock may be placed under quarantine, and you’ll be required to prove that the infection has been cleaned up before birds can leave your place alive.Give supportive care for chicken respiratory illness
The four possible outcomes to chicken respiratory illness are as follows:-
Complete recovery, typically within two to four weeks
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The chicken recovers, but becomes a long-term carrier of the infection
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Chronic (long-term) illness
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Death
The chicken cold that never goes away (or comes back again and again) is probably chronic respiratory disease (CRD), caused by mycoplasmosis.
Chicken respiratory diseases are highly contagious. They cause a lot of trouble year after year in infected flocks, which are constant threats to uninfected flocks. You can’t tell which recovered birds are carriers of infection without testing. Antibiotics make affected chickens feel better and may save a few that would have died without treatment, but antibiotics don’t cure the infection in carrier birds or eliminate the disease from the flock.
If you discover respiratory illness in your flock, you’re faced with a very difficult decision: culling, depopulating, or controlling. Your three choices aren’t easy:-
Cull (another word for euthanize) affected birds to prevent spread of the disease in the flock.
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Depopulate the flock (euthanize all birds) to eliminate the infection. Then, clean up and start over.
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Live with the infection, using vaccination or medication to control illness.
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Self-impose a quarantine on your flock.
Don’t move birds in or out.
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Isolate affected birds in a hospital pen and provide TLC.
Keep the hospital pen super-clean. Avoid dust and dirty bedding, which irritate sore lungs and sinuses.
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Use an antibiotic that is labeled for chicken respiratory illness, according to label directions.
Products with erythromycin, tetracycline, or tylosin are good first-line antibiotic choices that are available at many feed stores.
Consult your veterinarian if you want to treat laying hens, because no antibiotic is approved for use by U.S. flock keepers for laying hens.