Probably one of the most common problems we see is Marek's disease in small flocks of birds.
It causes great distress as it is often seen in pullets between 12 and 20 weeks of age and will be fatal. The control of the disease is difficult and you need to have a good understanding of the basic principles in order to reduce the chance of your birds becoming infected.
Marek's is caused by a Herpes virus which can survive for long times in the environment. Experimentally it is thought that in feather dust it can survive for at least 12 months and it is this problem which leads to it being so common.
Marek's disease is a common viral disease that is caused by a herpes virus. It is named after Josef Marek who first described it in 1907.
Marek's disease spreads through the lymphoid tissue and affects the skin or nerves and organs, causing tumours in the kidney, liver, spleen, lungs, heart, and ovary. Chicks older than 6 weeks can be affected but it is more common in chickens between 12 and 28 weeks old.
Photo: Paralysis caused by Marek's disease in a Silkie chicken. Photo courtesy of the excellent Chickenvet.