Last Updated: 30/04/2026
5 Common Diseases that Cause Feather Loss in Birds
Feather loss in birds isn't always just a normal moult. Discover the five most common medical conditions - including viral infections, mites, and nutritional issues - that cause feather damage, and find out how a veterinarian can help your bird recover.
Author: Dr Emilee Lay BVSc BSc (Vet) Hons
Reading Time: 4 minutes - short read
While many owners assume feather loss is just normal moulting, it is important to rule out underlying medical issues, as many of the diseases that cause feather loss can lead to long-term damage or even death. Identifying these early is vital, as birds often hide signs of illness until they are extremely unwell.
Viral Infections: PBFD and Polyomavirus
Psittacine Beak and Feather Disease (PBFD)
One of the most common causes of feather loss is Psittacine Beak and Feather Disease (PBFD), a circovirus. It disrupts keratin formation, leading to stunted, discoloured, or missing feathers and misshapen beaks.
- How it is spread: through faeces and feather dust
- Diagnosis: combination of clinical signs and PCR testing
- Treatment: is unrewarding, and there is no definitive cure. Although birds can live a reasonably good quality of life with this disease, they are often susceptible to other infections and illnesses
- Prevention: disinfecting the environment using F10, quarantining any new birds, and testing them as necessary
- Common carriers include lorikeets, budgies, and lovebirds
Bird polyomavirus
Similarly, bird polyomavirus symptoms include feather discolouration and deformities when chronic. In the acute form, it generally presents with vomiting, regurgitation, and blood loss. In budgies, it specifically affects the wing and tail feathers, which may fail to develop properly.
- How it is spread: through exposure to bodily fluids and dander from affected birds
- Diagnosis: PCR testing
- Treatment: limited, mainly being aimed at managing any secondary infections
- Prevention: disinfecting the environment using F10, quarantining any new birds, and testing them as necessary
Bird skin mites
Skin mites, specifically Knemidocoptes spp. (or Scaly mite), are common. They cause significant skin thickening and feather loss. Scaly face mite is common in budgies and characterised by crusting around the nostrils, head, and legs.
- Treatment: Ivermectin-based products. In severe cases, secondary infections may require antibiotics.
- Management & prevention: thorough disinfection of the environment and repeat treatment of all affected and exposed birds is a must.
Bacterial folliculitis
Inflammation of the feather follicles due to bacteria can cause intense itching. This leads to self-trauma, redness, and discharge from the follicles, resulting in patchy feather loss.
Learn more about How to Stop Bird Feather Picking.
Feather cysts
Similar to an ingrown hair, a feather cyst occurs when a growing feather cannot protrude through the skin and curls within the follicle, forming a large mass. They generally occur along the primary feathers of the wings.
To understand more about feathers and their growth, see our guide on Understanding Bird Feathers.
Nutritional and liver disorders
Inappropriate all-seed diets lack essential vitamins and can lead to fatty liver disease. This affects keratin production, often causing feathers to develop an abnormal yellow shade.
Learn more about the best diets for birds in our Beginners Guide to Bird Care and What Should Birds Eat?
Learn more about the best diets for birds in our Beginners Guide to Bird Care and What Should Birds Eat?
Because many of these conditions can lead to long-term damage or death, a thorough workup by an avian vet is essential to determine the correct treatment plan.
Bird Feather Disease FAQs
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Thu 30 Apr 2026
Edited by Dr Gillian Hill BVSc (Hons)Dr Emilee Lay BVSc BSc (Vet) Hons
Veterinarian
Dr. Emilee graduated from the University of Sydney in 2018 with a Bachelor of Veterinary Science and Bachelor of Science (Veterinary Studies) and as a student worked for a number of years as a small animals and exotics nurse in clinics across Sydney. She is currently a practicing small animal and exotic vet along the Coast. Emilee holds a special passion for avian and exotic medicine (bunnies being her favourite patients), as well as animal behavioural medicine!
