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Dewormer for a Laying Hen

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The early bird gets the worm, and it's a good thing. When your laying hen gets worms, not so good. It's quite common for chickens to have a low-level intestinal worm load. A few worms won't really affect most chickens, but a high level of infestation is a different story. Then your hens require deworming.

Chicken Worms

The most dangerous intestinal worms in chickens are ascarids, or large roundworms. These worms grow up to 4.5 inches long. Symptoms include diarrhea, weight loss and inactivity. In a worst-case scenario, roundworm cause intestinal blockage, killing the hen. Tapeworms also affect chickens. You might see ricelike tapeworm segments in your affected hens' feces. Cecal worms live in the chicken's cecum but aren't particularly damaging. That's not true of threadworms, which can erode your poultry's intestinal lining, killing them.


Piperazine, marketed under the name Wazine for poultry, is the only chicken dewormer available over-the-counter. It's the same dewormer you might purchase for kittens and puppies, but it's added to drinking water, rather than given by mouth, for administering to chickens. Piperazine gets rid of large roundworms. To treat your hens, remove water at night, unless it's very hot outside. Provide the water containing piperazine the next morning. Repeat treatment the next month to disrupt the ascarid's life cycle, then deworm as necessary. Don't use it on any chickens you intend to slaughter within three weeks' time. Discard eggs from hens for 10 days after deworming.

Veterinary Prescription

Other dewormers for chickens are available only by veterinary prescription, even if they are available over-the-counter for other livestock. For example, if you have horses you probably deworm them with ivermectin -- but don't try to use the equine paste dewormer on your hens. Your vet prescribes a pour-on formula for chickens. It's the same with other common dewormers such as panacur and febendazole. Don't try to save money by diluting dewormers designed for livestock or pets for your poultry. You could end up seriously harming or even killing your birds.

Fecal Counts

Rather than deworm, you can gather fresh samples of your hen's poop and take it to your vet for fecal testing. She'll be able to tell you whether your hens have a significant worm load and whether you should deworm. She can also write you a prescription for a dewormer that might kill particular worms infesting your flock. There's no need to conduct separate fecal tests, because if one hen in your flock has a heavy worm load, odds are most of them do.