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Feather loss (Photo: BIOMIN / Mehrdad Karimi)

Impaired feathering or feather loss

Impaired feathering or feather loss can manifest in various ways, such as birds losing feathers on neck, back, bottom, around neck or chest. It may be more or less extensive and result from a variety of factors.

Importance and Problems

In poultry, feathers serve important roles in terms of protection and insulation of the body. While molting, or renovation of older feathers by new ones, is a natural process occurring in mature layers upon completion of a laying cycle, feather loss or impaired feathering may be indicative of other problems in the farm.

Feather-related problems in poultry can be roughly divided into two groups of causes, either:

  1. They are not properly developed (linked to feather formation) which is often related to nutrition or the presence of mycotoxins.
  2. They are pulled off by birds (feather pecking), which is a management-related issue.
    Feathers (broiler at 3 weeks) (Photo: BIOMIN)
    Feathers (broiler at 3 weeks)
    Photo: BIOMIN

    Causes of losing feathers

    In each case it is critical to understand the foundation of the problem so that it can be properly solved (see table). Stressful conditions in the barn, especially during brooding, such as heat, cold and existence of air currents, among others, can result in feather loss and poor feather quality in the birds. In this case, it is crucial that the behavior and interaction of animals is observed.

    Often, feather pecking and pulling can also be triggered by inadequate intake of nutrients. Due to the high protein content in feathers, higher protein levels in feed may encourage faster feather development and shedding.

    Imbalance of amino acids in the feed, particularly sulphur amino acids cysteine and methionine, may cause feather abnormalities and/or rough feather appearance. The dermotoxic effect of trichothecenes mycotoxins, such as T-2 toxin and others may also contribute to low feather quality along with other negative effects, such as oral lesions and decreased performance.

    Overall, excessive feather loss or impaired feathering adversely affects feed conversion, as birds have to allocate extra energy from the diet to compensate for heat loss. As such, management, housing and nutrition should be optimized to reduce this occurrence.


    Potential causeChecklistCorrective action
    T-2 toxin (T-2)/Deoxynivalenol (DON)/ Other trichothecenes

    Feathers are narrow due to radiomimetric injury to the developing barbs.

    • Origin of raw materials from supplier/region with history of DON contamination.
    • Check average contamination levels.
    • Positive for DON in raw materials (ELISA) or feed (HPLC).
    • Prevent mold growth, purchase clean raw materials.
    • Avoid contamination of feed bins or feed/water lines by stale, wet or moldy feed.
    • Add an effective mycotoxin deactivator in the feed.


    Potential causeChecklistCorrective action
    Non-starch polysaccharides (NSP)

    Impairment of amino acid digestibility can affect gut health and leads to impaired gut integrity. Rough raw materials, overcooked soya, enzymatic quality formulation and together with NSP's can result in impaired feathers.

    Check NSP levels. Check feed composition and commodities.Maintain the correct levels of NSPs. Adapt commodities for best feed quality.
    Amino acid (AA) deficiency/unbalance

    Impaired feather formation and feather pecking.

    • Check levels of sulphur amino acids (TSAA) in the diet.
    • Ratio TSAA/Lys/Arg/Thr.
    • AA scale at feed mill.
    • Maintain the correct levels of sulphur amino acids.
    • Increase level of synthetic Amino Acids in the diet.


    Potential causeChecklistCorrective action

    Poor feathering, ruffled feathers and pecking.

    Presence of red mites in the barn during the night.
    • Flame cages during withdrawal period.
    • Clean egg belts during withdrawal period.
    • Increase biosecurity level.
    Infectious Bursal Diesease (IBD)

    IBD is very immunosuppressive and leads to impaired feathering.

    Check maternal antibody levels.Adapt vaccination program to meet the risks of infection as per field challenge.


    Potential causeChecklistCorrective action
    High house temperatures

    Pecking when associated with low humidity, also possibility of nutritional deficiencies.

    Check temperature and ventilation system.Maintain correct temperature and ventilation.

    Direct competition for feeders and drinkers leading to pecking, or nutrient deficiencies.

    Maintain correct ratio of feeders and drinkers.Reduce placement numbers.

    Find this handy checklist and more in our Science & Solutions special issue.



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