M.S.K. Mashishi



Feather loss

  • Loss of feathers can be caused by mite infestations. These cause irritation and result in scratching and loss of feathers.
  • Deficiency of certain nutrients and stress factors such as overcrowding can also result in pecking among chickens (cannibalism), leading to the loss of feathers.

Clubbed down

This condition is the result of failure of the feathers to rupture from their sheaths. The underlying cause is vitamin B2 (riboflavin) deficiency.


Parasitic infestation

Different parasites can be seen on the head and body of chickens. These parasites appear as black, brown or red "spots" on chickens. These are mites, fleas, lice and ticks.


Pox is a viral disease that is transmitted by mosquitoes. Pox sores are seen on the unfeathered areas such as the head, neck, feet and legs. The sores begin as red pimples which develop into pimples filled with fluid (vesicles) and then pus (pustules). Finally, as the pustules burst open, crusts or scabs form.


  • Any stress-related factor such as overcrowding or bringing new birds into the flock will cause pecking.
  • Salt deficiency can also be a cause.
  • Chickens can also be seen with bite wounds from rats.
Pale (anaemic) skin
  • Chicken mites survive by sucking chickens' blood. With excessive mite infestation a lot of blood will be lost, resulting in an anaemic chicken with a pale skin, wattles and comb.
Yellow skin
  • Yellow skin can be normal or abnormal. Chickens that are fed yellow maize as part of their diet have a yellow skin.
  • Abnormally yellow skin is mostly seen in the case of the disease called
  • Aegyptionellosis, which is caused by a blood parasite that infects the red blood cells.


Blue skin (cyanosis)
  • This is seen in any severe condition of the bloodstream when bacteria (septicaemia) or viruses (viraemia) are circulating. In diseases such as Newcastle disease, wattles may sometimes show a bluish discoloration.

Leg conditions

Scaly legs
  • This condition is caused by mites and is frequently seen in backyard chickens. The legs are rough and scaly. The mites burrow under the skin of the legs and cause thickening and roughening of the scales.
  • This condition can be treated by dipping the legs in an acaricide.
  • Broken bones are often seen as a result of trauma.
  • Deficiency or imbalance of calcium and phosphate causes bones to break easily.
Swollen joints (arthritis)
  • The germ that usually causes swollen joints in chickens is Mycoplasma synoviae and Staphylococcus aureus. The most commonly affected joints are the hocks.

Marek's disease

  • This disease can be seen in two forms. The one affects the internal organs whereas the other affects the nerves. When the thigh and leg nerves areaffected, chickens lie on the ground with one leg backwards and the other turned forwards. Skin lesions are sometimes seen with Marek's disease.
Curled toe paralysis
  • This condition may be seen in chicks if their feed has been low in vitamin B2. The toes frequently curl inward and they may be unable to stand.
  • Rickets is caused by a relative or absolute deficiency in calcium, phosphorus and/or vitamin D3 or imbalances in the ratio of these nutrients.
  • Chickens with rickets walk with difficulty and have soft bones and beaks.


  • Parasites such as mites and fleas can be killed and controlled by using powder chemicals, e.g. carbadust. Chicken houses can also be sprayed with a chemical such as 10 % malasol to kill the parasites living in cracks and crevices.
  • Feed a good-quality diet or give mineral supplements where indicated.


For further information contact your nearest animal health technician or state/private veterinarian


Animal Health for Developing Farmers
ARC-Onderstepoort Veterinary Institute
Private Bag X05, Onderstepoort 0110
Tel (012) 529 9158


Resource Centre, Department of Agriculture
Tel (012) 319 7141/7085



Compiled by
Directorate Communication, Department of Agriculture
in cooperation with ARC-Onderstepoort Veterinary Institute

Printed and published by Department of Agriculture

and obtainable from Resource Centre, Directorate Communication
Private Bag X144, Pretoria, 0001 South Africa
This publication is available on the web:


Information provided by
Animal Health for Developing Farmers
ARC-Onderstepoort Veterinary Institute
Private Bag X05, Onderstepoort 0110
Tel (012) 529 9158