Budgerigars, or parakeets, shed their old feathers and grow new ones when they moult. Pet parakeets seem to be in a perpetual moult because they live in temperature controlled climates, according to the book "Parakeets: Your Happy Healthy Pet." But even pet parakeets tend to moult most of their feathers just one time a year. Healthy moulting differs from the bird disease commonly known as French moult.
Moulting parakeets loose entire feathers, which you will see at the bottom of the cage. Tail feathers tend to be the first feathers dropped. Aglets replace these fallen old feathers. Aglets resemble small tubes, such as the ones on the ends of shoelaces. But on parakeets, aglets are shafts for new feathers. Made of keratin -- the same material as their claws and beaks -- aglets protect the bird's newly sprouting feathers. But moulting parakeets should never sport bald patches, according to "Parakeets for Dummies."
Growing new feathers itch. Moulting parakeets, often unable to reach all of the places where they itch, often pester surrounding people for scratches. However, their sensitive skin causes parakeets to be more irritable and more prone to biting. Parakeets that live in small flocks or bonded pairs may avoid human contact and prefer to have their itches scratched by other parakeets.
Moulting parakeets flap their wings more often than usual, no matter if their wings are clipped. Vigorous flapping helps loosen old, tattered feathers. This may also promote blood circulation to new feathers and help to stimulate their growth. Because parakeets need to flap their wings during the moult and to encourage them to exercise, parakeet owners should purchase cages or aviaries as large as they can afford, recommends "Parakeets for Dummies."
Parakeets sporting bald patches may be infected with the polyomavirus or French moult. This mostly affects parakeet chicks entering their first moult at 5 or 6 weeks old and is potentially fatal. Parakeets with French moult often shed their flight feathers first on both wings. All the feathers on the wings fall off except for two long primary feathers on the outermost parts of the wings. Body feathers can fall out too. Spots of dried blood pepper the bald skin. These blood drops are from shedding feathers. Aglets grow poorly and cannot support new feathers. Eventually the bird dies if it is not given any veterinary treatment and dietary supplements. Only a vet can accurately diagnose French moult.