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Are eggs safer from backyard chickens?

October 30, 2014

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Owners should be aware of possible residues in backyard chicken eggs

Eggs don’t get any fresher than the ones produced by backyard chickens—but are they safe to eat? Not always. Professor Lisa Tell, a UC Davis avian veterinarian says that depends on potential residues of drugs or pesticides in the eggs.  

“Backyard chickens occasionally get sick and it’s important for owners to consult a veterinarian for them just as they would for their dog or cat,” Tell said. “If the birds are treated with antibiotics, antiparasitics, or other medications, residues from those treatments can remain in an animal’s system for various lengths of time, during which the eggs should not be consumed.”

Tell emphasizes the importance of working with an avian veterinarian who can advise the owners on how long to withhold the eggs before they are safe to eat. Those veterinarians depend on the Food Animal Residue Avoidance and Depletion (FARAD) program—a unique USDA-sponsored service that consists of regional units at the UC Davis School of Veterinary Medicine, North Carolina State University, Kansas State University and the University of Florida.

“It is important for people to be aware of how treatment of chickens with drugs or pesticides can result in drug or pesticide residues in the eggs,” said Tell, who serves as director for the Western region of FARAD. “If chickens are free ranging, they potentially have access to things like rodenticides that the owners might not be aware that the chickens are ingesting and rodenticide residues can show up in eggs. In addition, any pesticides or herbicides used in home gardens could be ingested by the birds munching on plant material and egg residues could be problematic.”

Kansas State Professor Ronette Gehring, who directs the Midwest Region of FARAD emphasized in a recent press release that owners need to be very careful using any medications.

“It’s important that if owners buy medications over the counter to treat their flock, they closely follow the directions on the label,” Gerhing said. “This includes only using the drug if it is specifically labeled for chickens laying eggs and only for the diseases listed on the label, at the exact dose, dosing interval and duration of treatment given in the instructions.”

There is usually a withdrawal time listed on the medication’s label, which is the period when the eggs shouldn’t be eaten. But there aren’t many drugs specifically labeled for backyard chickens; most are formulated for large commercial operations. FARAD provides drug use advice to veterinarians, who can let owners know when it is safe to consume their chickens’ eggs.

Owners should also keep in mind that they may need to thoroughly clean coops, water and food dishes after chickens have stopped receiving any medications as residues can remain in those environments.

The UC Davis veterinary hospital offers avian veterinary care through the Companion Exotic Animal Medicine & Surgery Service. Owners can call the main small animal clinic for an appointment at 530-752-1393.  

UC Davis is growing California

At UC Davis, we and our partners are nourishing our state with food, economic activity and better health, playing a key part in the state’s role as the top national agricultural producer for more than 50 years. UC Davis is participating in UC’s Global Food Initiative launched by UC President Janet Napolitano, harnessing the collective power of UC to help feed the world and steer it on the path to sustainability.



Trina Wood, Communications Officer

530-752-5257; tjwood@ucdavis.edu