ABSTRACT
Juvenile budgerigars exhibit continued growth of flight, tail and contour feathers. As the feathers are soft and curled, it gives the bird the appearance of a feather duster. Affected birds have excessively long and curled feathers; they are unable to fly and make a barely audible noise. Most die within the first few years of life. They may actually be benign neoplasms of the feather follicle. Several dermal papillae form in each follicle, resulting in a tangle of feathers that fail to erupt from the skin. Treatment of individual cysts can be conservative, simply lancing and expressing the contents of the cyst. Recurrence is common, but surgical excision of the affected follicle is generally curative. Colour in birds is the result of a combination of feather structure (affecting the passage or reflection of light), melanin pigments (black, grey and brown) and carotenoid pigments (yellow and red). Poultry with thyroiditis demonstrate changes in feather quality and colour.
