Parasitic diseases in poultry

A parasite is an organism that lives in or on another organism (referred to as the host) and gains an advantage at the expense of that organism. The two types of internal parasites that affect poultry are worms and protozoa. Usually, low levels of infestation do not cause a problem and can be left untreated. Clinical signs of a parasite infestation include unthriftiness, poor growth and feed conversion, decreased egg production, and, in severe cases, death. Also, parasites can make a flock more susceptible to diseases or worsen a current disease condition. External parasites can also cause problems for small flock poultry producers and occasionally for large flock producers. These unwanted visitors can be brought into the poultry house by wild birds or new birds being added to the flock. All new birds should be checked for parasites before they are mixed with the original flock.