Merck Animal Health Announces EXZOLT^® (fluralaner oral solution) for Northern Fowl Mites in Backyard Chickens

July 6, 2026

Oral solution delivers convenient and effective mite control for laying hens and replacement chickens in backyard settings

RAHWAY, N.J., July 6, 2026 – Merck Animal Health, known as MSD Animal Health outside of the United States and Canada, a division of Merck & Co., Inc., Rahway, N.J., USA (NYSE:MRK), today announced EXZOLT^® (fluralaner oral solution) is now available for the treatment and control of northern fowl mites (Ornithonyssus sylviarum) in laying hens and replacement chickens in backyard settings.

Northern fowl mites are a persistent external parasite that feed on birds and can quickly affect flock comfort, well-being and productivity. For backyard chicken owners, infestations can pose challenges for bird health, egg production and the overall home environment. Although mites do not live on people or pets, they may bite and cause irritation.

EXZOLT is an oral solution used in commercial chicken production and is now available for use in backyard flocks. Each dose of the product is given in two administrations via drinking water, seven days apart, providing an effective option without the need for injections or individual bird handling.

“Backyard chicken owners need effective parasite control options that are easy to use and protect the health of their birds without disrupting daily care,” said Charles Broussard, D.V.M., senior account manager for poultry sales, Merck Animal Health. “EXZOLT provides a practical, water-based treatment approach with strong efficacy, helping owners manage northern fowl mites while supporting the comfort and productivity of their birds.”

Key benefits include:

Fast-acting control: Starts killing mites within hours to help quickly restore flock comfort as well as prevent the spread to other birds or the household
High efficacy: Demonstrated 99.9% effectiveness in studies and uses the same product formulation as commercial production
Reliable treatment: One treatment regimen consists of two doses administered seven days apart for sustained control
Convenient administration: Delivered through drinking water with no handling required, helping to minimize stress to the birds
Reduces spread: Prevents mites from spreading to other birds or the household
Withdrawal period: Zero-day egg withdrawal and 11-day meat withdrawal

EXZOLT is available by prescription in a 4 mL presentation. For more information about EXZOLT for backyard chickens, visit https://www.merck-animal-health-usa.com/producers/poultry/.

IMPORTANT SAFETY INFORMATION: EXZOLT^® (fluralaner oral solution)
Not for use in humans. Keep this and all drugs out of the reach of children. Accidental exposure may cause skin and eye irritation. Accidental ingestion may cause gastrointestinal disturbances and hypersensitivity reactions in humans. Chickens must not be slaughtered for human consumption for 11 days after the last treatment. No egg discard is required when used according to the labeling. For complete safety information and product dosing instructions, refer to product label.

Merck Animal Health announces EXZOLT^® (fluralaner oral solution), a proven oral solution trusted by commercial egg producers, is now available for backyard flocks in a new 4 mL presentation to treat and control Northern Fowl Mites in laying hens and replacement chickens.

About Merck Animal Health

Merck Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA, is a global animal health business committed to The Science of Healthier Animals™. For more than 130 years, we have pioneered groundbreaking science. Today, we are driven by continuous innovation to develop breakthrough medicines, vaccines and technology. Rooted in direct experience on the farm and in the clinic, we work hand in hand with our customers every step of the way. Our singular focus is to empower those who care for animals, helping them manage their vital responsibility with confidence. Because when it comes to animal health, no one sees it like we do. For more information, visit www.merck-animal-health.com and connect with us on LinkedIn, Facebook, X (formerly Twitter) and Instagram.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA

This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2023 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).