A coughing duck usually has a respiratory irritant or infection. Unlike mammals, ducks lack a true diaphragm, so their coughs sound different: more like a soft wheeze, a repeated gasping motion, or a raspy honk rather than the sharp hack you’d expect from a dog or cat. The cause can range from something as simple as dusty bedding to a serious infection, so identifying the trigger matters.
Ammonia and Dusty Bedding
The most common and fixable cause of coughing in backyard ducks is poor air quality in their housing. Ammonia gas builds up from droppings and wet bedding, and duck housing tends to stay damp. Research on Pekin ducks found that ammonia exposure causes direct damage to the trachea and lungs, triggering inflammation even at moderate concentrations. The recommended threshold for poultry housing is no more than 25 parts per million. If you can smell ammonia when you walk into the coop, levels are already too high.
Dusty straw, moldy hay, and fine shavings also irritate the airways. Ducks housed on organic bedding are continuously exposed to airborne fungal spores and particulates, especially when bedding gets stirred up. Switching to cleaner bedding, improving ventilation, and mucking out more frequently often resolves coughing within a few days if air quality was the problem.
Aspergillosis From Mold Exposure
If your duck’s cough doesn’t improve with cleaner housing, a fungal infection called aspergillosis is worth considering. Aspergillus fungi thrive in damp organic material, and the spores become airborne when conditions dry out. Hot, humid climates and poorly stored bedding are the biggest risk factors. Studies have confirmed a strong correlation between fungal contamination in litter and the concentration of fungal spores in the air, meaning the bedding itself is often the main reservoir of infection.
Aspergillosis affects the lungs and air sacs. Infected ducks may breathe with an open beak, lose weight gradually, and become lethargic. It’s notoriously difficult to treat once established, which makes prevention the priority: store bedding in dry conditions, avoid using visibly moldy straw, and keep housing well ventilated.
Gapeworm
Ducks that forage on the ground can pick up a parasitic worm called Cyathostoma bronchialis, the gapeworm species specific to ducks and geese. These worms live inside the trachea, physically blocking airflow. A duck with gapeworm will stretch its neck, shake its head, and gasp with an open mouth, sometimes appearing to “yawn” repeatedly. The Merck Veterinary Manual rates its pathogenicity as severe, and young birds are hit hardest. In serious cases, the worms can cause suffocation.
Your vet can confirm gapeworm by examining droppings or performing a tracheal swab. Treatment with an appropriate dewormer is usually effective when caught early. Ducks that free-range on soil where wild birds have been are at the highest risk.
Bacterial and Viral Infections
Several bacterial infections produce coughing alongside nasal discharge, swollen sinuses, and watery eyes. Riemerella anatipestifer is one of the more common bacterial pathogens in domestic ducks specifically. Infections caused by Mycoplasma species can also cause rattling breathing sounds, coughing, sneezing, and a frothy discharge from the eyes, though a related species called M. imitans is more commonly found in waterfowl than the better-known M. gallisepticum of chickens. Pasteurella multocida, the bacterium behind fowl cholera, can cause acute respiratory distress that progresses rapidly.
On the viral side, Newcastle disease causes respiratory and digestive symptoms including coughing, sneezing, eye tearing, and breathing difficulty, sometimes followed by neurological signs like twisted necks or circling. Low-pathogenic avian influenza can cause mild coughing, sneezing, and nasal discharge, though many ducks carry it without showing any symptoms at all. If multiple birds in your flock develop respiratory symptoms around the same time, a contagious infection is the most likely explanation.
Something Stuck in the Throat
Ducks are enthusiastic foragers and occasionally swallow something that partially lodges in the throat or airway. A foreign body obstruction tends to come on suddenly, with no buildup of symptoms beforehand. You’ll typically see immediate distress: repeated head shaking, open-mouth breathing, and a harsh, raspy cough that sounds distinctly different from the wet, rattling cough of an infection. If the object fully blocks the airway, the duck may become silent and struggle to breathe at all. This is an emergency. A partial obstruction can sometimes mimic an infection, with persistent wheezing and coughing that lasts days if the object isn’t removed.
Blocked Nostrils From Lack of Water Access
Ducks need water deep enough to submerge their entire head, not just to drink but to clear their nostrils. They dip their bills underwater and blow air through their nostrils to flush out debris, dried mucus, and feed particles. The European Food Safety Authority notes that a minimum water depth of 10 cm is necessary for ducks to perform this behavior. Without it, nostrils become dirty and eventually blocked, which can lead to snorting, coughing, and secondary respiratory issues.
If your ducks only have access to a nipple waterer or a shallow dish, this alone could explain the coughing. Providing a bucket or trough deep enough for full head dipping often produces a noticeable improvement quickly.
Signs That Need Urgent Attention
Some respiratory symptoms indicate a duck is in serious trouble. Open-mouth breathing at rest, a visible bobbing of the tail with every breath, and puffed-up posture with closed eyes all signal significant respiratory distress. A duck that stops eating, isolates from the flock, or has thick discharge clogging its nostrils needs veterinary care promptly. Respiratory infections in birds can deteriorate fast because their air sac system, while efficient for flight, also means infections spread quickly through the body.
If only one duck is coughing and it’s acting otherwise normal, eating well, and keeping up with the flock, start by checking your housing conditions, water access, and bedding quality. If the cough persists beyond a few days, worsens, or spreads to other birds, that points toward infection or parasites rather than an environmental issue.