New university research shows that free range hens fed Orego-Stim, containing 100 percent natural oregano essential oil, had a lower mean roundworm count, lower tapeworm infections and that the relative risk of tapeworm infection was reduced by up to 54 percent.

The trial was conducted at North Carolina State University in conjunction with independent feed additive manufacturer, Anpario

Gastrointestinal parasitic worms are a concern for the poultry industry, as they can affect bird health, welfare and production performance,” said Laura Corbett, Anpario’s poultry product technical manager. 

“Tapeworms are a common cause of infection. However, roundworm is the most concerning as infection is associated with reduced health and welfare, poor feed efficiency, reduced performance and, in severe cases, death. Caecal roundworms are also associated with blackhead transmission, which can be a serious issue for laying hen flocks.”

Corbett also stated that “Previous research by Permin et al., (1999) has confirmed that free range and backyard egg production systems have a higher risk of worm infection, and that prevalence of worms may also be greater in deep litter systems in comparison to caged systems.”

“The mode of transmission also differs depending on the type of worm, with some being passed directly from bird to bird though the faecal/soil/bedding oral route and others which have the ability to reside in earthworms, which infect the bird once ingested,” explained Corbett.


540 Bovans Brown hens were randomly assigned to one of three dietary groups; a basal diet fed during rear and lay (Control), OSP included at 300g/t during lay only or OSP included at 300g/t during rear and lay. Hen faecal and caecal samples were then tested for roundworm (Ascaridia galli and Heterakis gallinarum) prevalence and the presence of tapeworms at 16 and 41 weeks of age.

The results showed that pullets fed Orego-Stim during the rearing phase had a lower mean roundworm count, as did the hens fed Orego-Stim during rearing and lay. Tapeworm infections were also lower in hens fed Orego-Stim, either during lay only or during both rear and lay, and the relative risk of tapeworm infection was reduced by up to 54 percent in hens fed Orego-Stim. 

In summary, supplementation of Orego-Stim Powder in pullet and layer diets helped to reduce mean counts of roundworm and reduced the presence of tapeworms. “These impressive results highlight the effectiveness of Orego-Stim supplementation in both pullets and layers, offering an effective natural solution to worm challenges in free-range systems”, Corbett concluded.

Orego-Stim is a high quality eubiotic composed of 100% natural oregano essential oil. Natural OEO has many properties including antimicrobial, antioxidant, anti-inflammatory and immunomodulatory functions and has been shown to support healing and repair of the gut lining.