Excessive feather plucking can be a sign of a medical or psychological disorder. Underlying reasons include:

• Hormonal changes
• Malnutrition
• External and internal parasites
• Bacterial or fungal infections of the skin or feather follicles
• Allergies
• Environmental stress
• Overstimulation of a nervous bird
• Not enough playtime, attention, activity or exercise
• Inappropriate handling
• Insufficient (full-spectrum) light
• Fear of danger from other pets

Normal feather plucking when your bird is preening or molting is not a cause for concern. But you should take your bird to the veterinarian if the activity increases beyond the norm. It is a good idea to keep a record of when this feather plucking takes place and under what circumstances. This information may help your veterinarian with a diagnosis.