All About Feathering

By Dr. Justin Fowler

Feathers are one of the unique adaptations of birds.  These structures, which are essentially highly specialized scales, must be both light and flexible enough to control flight but strong enough to withstand the forces associated with flight.  They are an important part of the integumentary system, with over 75% of a bird’s skin being covered with feather tracts.  Feathers play a key role in regulating body temperature and protecting the bird from external injury or infection.

Feathers, like muscles or eggs, are made of protein.  Thus, there are aspects of nutrition that can impact feather development and integrity.  As would be expected, higher protein diets lead to a greater rate of feather regeneration, whereas diets containing <16% show the opposite.  The most common nutritionally-caused reason for poor feather development would be a deficiency in the critical amino acids that are needed to make the keratin in the feathers.  The sulfur-containing amino acids (cysteine and methionine) are the major constituent of feathers.  Cysteine can make up about 25% of the amino acid residues in keratin.

Obviously, the nutritional factors such as protein/amino acid content of the diet receive the most attention when it comes to feathering because that is what feathers are made of.  While abnormal feathering can certainly be an aid in diagnosing some of the nutritional deficiencies, it is typically a non-specific process.  With respect to nutrition, it is important to remember that early nutrition is key.  Producers need to maximize feathering through the early phases because problems with feather coverage that arise in the later periods are typically caused by damage that was done earlier on, and it is often too late to make nutritional fixes during this most financially important period.