QuailGuard®
QuailGuard®, the anthelmintic medicated feed for control of parasitic infection in wild quail was invented by Dr. Ronald J. Kendall (U.S. Patent No.: 10,583,124) through work in the Wildlife Toxicology Laboratory (WTL) at Texas Tech University. The product was developed with support from Park Cities Quail Coalition and the Rolling Plains Quail Research Foundation to address extensive parasitic infection in wild quail, particularly in the Rolling Plains ecoregion of Texas (Henry et al 2025; Henry et al 2025; Henry et al 2025). QuailGuard® was registered with the United States Food and Drug Administration (FDA) in May 2024 (FDA Drug Registration) and represents the first medicated feed article to be registered by the FDA for treatment of a wildlife species in their natural habitat that ultimately became commercially available (this made U.S. history). Here, we want to discuss more about the science behind QuailGuard® and provide scientific documentation and validation that at multiple FDA demonstration sites QuailGuard® is effective for parasitic control and supports enhanced and sustainable quail populations.
Quail populations, particularly in the Rolling Plains ecoregion of Texas and Oklahoma (an area about the size of the State of Michigan), experience dramatic population cycles usually on an approximately five- to six-year basis where peaks in population are followed by dramatic drops in that population (See Texas Parks and Wildlife graph).
Taken from Texas Parks and Wildlife Bobwhite Quail Forecast 2025-26
The goal of the WTL, through sponsorship provided by multiple organizations, was to identify a culprit for these population crashes and to achieve sustainable and huntable populations of wild quail for current and future generations. Wild quail populations across the United States in terms of sustainable and huntable populations have diminished over 80% from their original natural range. Although the focus in recent years has been on the Rolling Plains ecoregion of Texas and Oklahoma, this is a national conservation issue and is now expanding to other parts of the country (currently South Carolina).
To achieve our FDA registration, we had to prove that QuailGuard® was effective, safe, and that drug residues in the quail would diminish rapidly subsequent to the quail going off treatment Henry et al 2025, Efficacy; Henry et al 2025, Safety; Henry et al 2025 Dissipation). In addition, the WTL has proven both in the field and laboratory that QuailGuard® is very effective and toxic only to helminth parasitic infection (Suber et al 2025). It is extremely safe for wild quail at all ages, and the treated quail are safe for human consumption because of the rapid dissipation of the active ingredient, fenbendazole, from the quail body subsequent to the withdrawal of treatment (Suber et al 2026).
We have significant field evidence that quail populations are responding positively to QuailGuard® treatment. As an example, when we introduced QuailGuard® into a treatment zone in the Rolling Plains ecoregion of Texas, we saw a 300% increase in wild quail (Henry et al 2024). Additionally, in the Rolling Plains ecoregion of Oklahoma, we have seen similar results with > 300% increase in wild quail when we introduced QuailGuard® into the management paradigm (Leach et al 2025). What has been consistently demonstrated on our five FDA treatment sites, is that we have enhanced quail survival with treatment of QuailGuard®. For instance, in our Oklahoma study, we report an increase in two- and three-year-old birds in the quail population subsequent to QuailGuard® treatment. Similar results have been seen on W7 Ranch in Garza County, Texas, where we have seen a substantial increase in two-, three-, and even four-year-old quail in the population. Similarly, we are seeing these kinds of results on Snipes Ranch in Stonewall County, Texas. In short, we are seeing very large coveys of wild quail consistently throughout the hunting season, literally right up to the last day of the season. This has been observed by our FDA research ranch cooperators and our own personal investigations. Therefore, the data reveals that we are enhancing longer term survival of wild quail in QuailGuard®-treated zones. This did not occur on just one FDA demonstration site but has occurred consistently on five different sites located in Texas and Oklahoma.
Our science is supported by the validation work of our FDA demonstration ranch cooperators. For instance, on Snipes Ranch this past year, Joe Crafton, a ranch co-owner, kept detailed records of the quail coveys found throughout the 2025-26 quail season. He documented that 359 coveys of wild quail were seen in 59 hours of hunting with quail-hunting dogs on the ground. This represents approximately six covey finds per hour on average throughout the quail season. These are extraordinary find rates for wild coveys of quail, particularly at this time in history when across the United States huntable and sustainable populations of wild quail, particularly bobwhite quail, have been diminished greater than 80%. Snipes Ranch has been using QuailGuard® treatment for over seven years.
In addition, reports from our FDA demonstration ranch in southeastern Oklahoma represents average covey size of 18 quail per covey with many coveys having over 30 quail in the 2025-26 season. The quail manager stated, “This was the best season we have seen in over 20 years.” They have consistently been using QuailGuard® treatment for over five years.
In addition, the owner of W7 Ranch, J. David Williams, has publicly commented that a few years ago they had stopped wild quail hunting at his ranch because of insufficient quail to hunt, but after several years of QuailGuard® treatment, 20-25 coveys of wild quail (very large coveys) are consistently found in a five-hour or less hunting day. In fact, in the last week of 2026 season, Mr. Williams hosted a quail hunt in the afternoon of February 27, 2026, and found 18 coveys in less than four hours of hunting. Dr. Kendall was present to observe these numbers and validate that the quail population was sustained throughout the quail season and was still offering excellent hunting to literally near the last day of the season. This is a testimonial to QuailGuard® treatment sustaining quail survivability as validated by the continued existence of high-quality quail hunting up to the last day of the season on our FDA demonstration ranches that we have studied extensively.
Another demonstration ranch, Ribelin Ranch, has been using QuailGuard® for over five years as well. This FDA demonstration site has demonstrated consistently strong wild bobwhite quail populations even near the end of the season. For instance, on February 22, 2026, Dr. Kendall went out with the ranch owner and found 11 coveys of quail in less than three hours of hunting. Some of the coveys of wild quail were at least 25 birds and the ranch owner documented multiple coveys through video surveillance utilizing the QuailSafe® feed delivery systems. Over the last several years, Mr. Ribelin has reported that while he has huntable quail populations that are sustainable, oftentimes his neighbors have few, if any, quail. This again is a testimonial that QuailGuard® is assisting us in enhancing sustainable wild quail hunting opportunities.
QuailGuard® is distributed in 50lb bags as a crumble-type feed readily accepted by wild quail without any acclimation and is highly palatable and nutritious (Henry et al 2022).
Generally speaking, what is proven to be effective treatment is the utilization of QuailSafe® delivery technology, or other appropriate feeders, located with about one unit per approximately 200 acres of habitat. The integration of an electronic quail caller is even more effective in bringing the quail into the QuailSafe® delivery system where they can consume QuailGuard® in a safe environment protected from predators. In fact, we have extensive field observation of following quail covey sizes frequenting QuailSafe® treatment technology and covey sizes are definitely holding throughout the season (B. Ribelin, Personal Communication 2026).
Based on approval from FDA, QuailGuard® is utilized as an anthelmintic medicated feed treatment for a 21-day treatment period in the spring (particularly March) and in the fall (approximately September-October). Based on our data reporting to FDA, there is no withdrawal period required to harvest quail post-treatment based on the rapid elimination of the drug from the quail body (Henry et al 2025).
In April 2025, Dr. Kendall won the Texas Environmental Excellence Award in the Individual category for his work in quail conservation. This award is the highest of its kind in the State of Texas and is given by the Texas Commission on Environmental Quality and the Office of the Governor, Greg Abbott. The video highlights how the continued use of QuailGuard® makes a difference in quail enhancement and sustainability.
References
Henry, C., Brym, M.Z., Leach, J., Kendall, R.J. 2025. Efficacy of medicated feed to treat parasites of wild northern bobwhite quail (Colinus virginianus). Environmental Toxicology and Chemistry. 44(6):1538-1544. doi: 10.1093/etojnl/vgae017.
Henry, C., Brym, M.Z., Surles, J.G., Leach, J., Kendall, R.J. 2025. Safety of a medicated feed to treat parasites of northern bobwhite (Colinus virginianus). Environmental Toxicology and Chemistry. 44(4):1552-1560. doiI: 10.1093/etojnl/vgaf063.
Henry, B.J., Henry, C., Patel, D., Brym, M.Z., Kalyanasundaram, A., Leach, J., Kendall, R.J. 2025. Depletion of fenbendazole sulfone residues in northern bobwhite (Colinus virginianus) liver following medicated feed treatment. Environmental Toxicology and Chemistry. 44(6):1545-1551. doi: 10.1093/etojnl/vgaf026.
Suber, H.N., Arlowe, T.B., Valencia, H., Kaskocsak, A., Kinsey, K., Guerra, J., Colette, S., Summers, A., Surles, J.G., Kendall, R.J. 2025. Demonstrated laboratory effectiveness of an anthelmintic medicated feed for the treatment of Oxyspirura petrowi infections in northern bobwhite (Colinus virginianus). Environmental Toxicology and Chemistry. 44(11):3236-3242. https://doi.org/10.1093/etojnl/vgaf198.
Suber, H.N., Patel, D., Arlowe, T.B., Kaskocsak, A., Valencia, H., Kinsey, K., Robinson, W.R>, Kendall, R.J. 2026. Pharmacokinetics of fenbendazole and its bioactive metabolite oxfendazole in northern bobwhite administered an anthelmintic feed. International Journal for Parasitology. 10.1016/j.ijpddr.2026.100640
Henry, C., Brym, M.Z., Leach, J., KENDALL, R.J. 2024. Northern bobwhite (Colinus virginianus) population response to anthelmintic treatment in the Rolling Plains ecoregion of Texas, 2014-2016. International Journal for Parasitology: Parasites and Wildlife. 25:101006. doi: 10.1016/j.ijppaw.2024.101006.
Leach, J., Suber, H.N., Rivera, R., Conley, K.A., Lukashow-Moore, S.P., Surles, J.G., Kendall, R.J. 2024. Response of northern bobwhite (Colinus virginianus) and two parasitic nematode populations in western Oklahoma to anthelmintic supplemental feed. International Journal of Parasitology: Parasites and Wildlife. 25:101001. doi: 10.1016/j.ijppaw.2024.101001.
Henry, B.J., Brym, M.Z., Henry, C., KENDALL, R.J. 2022. Supplemental feeding of northern bobwhite (Colinus virginianus) and dietary requirements: a review. Wildlife Research. 49:89-99. https://doi.org/10.1071/WR20105.
