Merck launches FDA-approved oral treatment for northern fowl mites in backyard poultry

Merck has introduced Exzolt, an oral fluralaner treatment for northern fowl mites in backyard chickens, offering a non-invasive option backed by FDA approval and recent research support.

Merck Animal Health has begun selling Exzolt, an oral fluralaner treatment for northern fowl mites in backyard laying hens and replacement chickens, extending a product that won U.S. Food and Drug Administration approval in July 2025.

For poultry veterinarians, the development is notable because the FDA described Exzolt as the first approved oral product for this indication in chickens. The treatment is delivered through drinking water in two doses, seven days apart, which Merck says avoids injections and individual bird handling. The company also says the formulation begins killing mites within hours and showed 99.9% efficacy in studies.

Northern fowl mites are a common external parasite in small flocks and can undermine bird welfare, egg output and household hygiene. While the mites do not usually live on people or pets, they can still bite and cause irritation, making control important in backyard settings where owner compliance and flock handling can be difficult.

According to Merck, the product has a zero-day egg withdrawal period and an 11-day meat withdrawal period. Dr Charles Broussard, Merck Animal Health’s senior account manager for poultry sales, said the water-based approach is intended to give owners an easier way to protect birds without adding stress to routine care.

The launch follows Penn State research that supported the original FDA assessment, underlining the growing role of oral parasiticides in poultry medicine.

Image Source: MSD Animal Health