Respiratory Tract Infections in Chickens: Common Causes, Symptoms, and Care

Respiratory tract infections in chickens are illnesses that affect the upper or lower airways, including the nostrils, sinuses, trachea, air sacs, and lungs. In backyard flocks, this is not one single disease. It is a broad problem that can be caused by bacteria, viruses, fungi, or a mix of infection plus environmental stress.

A chicken with a respiratory infection may sneeze, breathe noisily, or have discharge from the eyes or nostrils. Some birds also show swollen sinuses, reduced appetite, weight loss, or a sudden drop in egg production. Signs can range from mild to severe, and they may spread quickly through a flock.

Several important poultry diseases can look very similar at home. Mycoplasma gallisepticum is a common cause of chronic respiratory disease in chickens. Infectious bronchitis can cause respiratory signs and also affect egg production and shell quality. Infectious coryza often causes facial swelling and nasal discharge. Secondary bacteria such as E. coli can make a mild problem much worse.

Because these diseases overlap so much, your vet usually needs to look at the whole picture: your flock history, age of birds, recent additions, housing, ventilation, and test results. That matters because some infections can improve with supportive care, while others may remain in the flock even after signs settle down.

Respiratory disease in chickens has many possible causes. Common infectious causes include Mycoplasma gallisepticum (often called chronic respiratory disease), infectious bronchitis virus, and infectious coryza caused by Avibacterium paragallinarum. Other infections, including Newcastle disease, avian influenza, fungal disease such as aspergillosis, and secondary bacterial infections like E. coli, may also affect the respiratory tract.

Environmental stress often makes infections more likely or more severe. Poor ventilation, ammonia buildup from wet litter, crowding, dusty bedding, temperature swings, transport stress, and mixing birds of different ages can all weaken respiratory defenses. A bird may look mildly affected at first, then worsen quickly once the airway is irritated or a second infection takes hold.

New birds are a major source of disease introduction in backyard flocks. Chickens can carry some respiratory pathogens without obvious signs, then shed them when stressed. That is one reason quarantine matters so much. Wild birds, contaminated equipment, shared feeders, and people moving between flocks can also spread disease.

Not every sneeze means a serious infection, but persistent or flock-wide signs should be taken seriously. Some respiratory diseases improve clinically yet remain present in the flock, which is why long-term management planning with your vet is often part of care.

Your vet starts with history and flock context. They will want to know the birds' ages, how many are affected, whether any new birds were added, vaccination history, housing conditions, egg production changes, and whether there has been recent stress, travel, or contact with wild birds. That background is often as important as the physical exam.

On exam, your vet may look for nasal discharge, swollen sinuses, eye changes, abnormal breathing sounds, weight loss, dehydration, and signs of lower airway disease. Because many poultry respiratory diseases look alike, diagnosis often needs testing rather than symptoms alone.

Common tests include swabs for PCR, bacterial culture, and sometimes serology or necropsy of a recently deceased bird. Merck notes that real-time PCR is commonly used for Mycoplasma gallisepticum, and PCR or culture can confirm infectious coryza. If infectious bronchitis, Newcastle disease, or avian influenza is a concern, your vet may recommend additional flock-level testing and may involve a diagnostic laboratory or state animal health officials.

This testing helps guide realistic next steps. In some cases, treatment focuses on supportive care and reducing spread. In others, your vet may discuss that birds can remain carriers, that recurrence is possible, or that flock biosecurity and future sourcing decisions are the most important part of long-term control.

Prevention starts with biosecurity and flock management. Buy birds from reputable sources, ideally programs that follow National Poultry Improvement Plan standards for monitored diseases such as Mycoplasma gallisepticum. Quarantine new birds before introducing them to your flock, and avoid borrowing equipment or mixing birds from swaps, shows, or unknown sources without a plan.

Housing matters too. Good airflow helps remove moisture, dust, and ammonia, all of which irritate the respiratory tract. Keep bedding dry, clean waterers often, avoid overcrowding, and reduce stress from sudden temperature changes or poor nutrition. These steps do not prevent every infection, but they lower the chance that a mild exposure becomes a serious outbreak.

Wildlife control is also important. Limit contact with wild birds, rodents, and shared outdoor water sources. USDA APHIS continues to emphasize biosecurity as the key defense against avian influenza, including for smaller and backyard flocks. Separate poultry from other species when possible, use dedicated shoes or boots in the coop area, and wash hands before and after flock care.

If respiratory disease appears, act early. Isolate affected birds, pause new bird introductions, and contact your vet. Early flock management can reduce spread, improve comfort, and help your vet decide whether testing is needed to protect the rest of your chickens.