Feather cysts are a common skin and feather condition in pet birds. It occurs when a new feather fails to come out and instead curls up under the skin, within the feather follicle. As the feather grows, the lump -- caused by the ingrown feather -- also continues to grow until the feather cyst becomes an oval or long swelling. At times, it can involve one or more feather follicles at a time.
A feather cyst can occur anywhere on the bird’s body. In parrots, however, it is commonly seen in the primary feathers of the wing. And although any bird can suffer from feather cysts, it usually occurs in parrots, macaws (blue and gold), and canaries, which usually have multiple feather cysts.
In most birds, feather cysts are caused by an infection or an injury to the feather follicle. In canaries, feather cysts are due to genetic predisposition.