Gastrointestinal Parasites of Free-Range Chickens – A Worldwide Issue

Gastrointestinal parasites with direct and/or indirect life cycles, namely Eimeria spp., Ascaridia galli, Heterakis gallinarum and Capillaria spp., are responsible for the most frequent and heavy economic losses in aviculture. The current review aimed to collect information about gastrointestinal parasites affecting poultry, as well as, research studies regarding parasitic diseases in free-range chicken production. From the references used in this review, 20% highlight research studies correlating prevalence of gastrointestinal parasites in free-range chickens and factors such as the production system, age and animal density, hygienic conditions and weather.Coccidiosis is responsible for the major economic losses in poultry farms. Diseases have different clinical signs and result in variable impacts on animals. Control programs include mainly vaccination, anti-coccidia and anthelminthic drugs, as well as, house cleaning and disinfection. This review concluded that coccidia and helminths are a global threat to free-range poultry production. More research in this area is necessary in order to understand the major factors influencing the prevalence of parasitic diseases in this type of poultry production. Also the search for new control strategies must be a priority, mainly using natural antiparasitic compounds and biological control approaches.