If you give just one dose of Fenbendazole it's not going to kill all the worms. This is what causes parasites as well as bacteria to develop resistances to the drug. That's why we have drug resistant bacteria in humans. People start to take the antibiotic, they feel better and so don't take the full regimen. Then over time the bacteria develops a resistance to the drug because it didn't kill ALL the bacteria off. THE SAME GOES FOR WORMERS FOR ANIMALS!!!
GIVE A FULL 5 DAYS of Fenbendazole. Then wait 2 weeks and do it again to get the new parasites that have hatched from the eggs in their system. Fenbendazole doesn't kill the parasite eggs only the parasites themselves.
We just finished the 1st 5 days of treatment for our chickens for gapeworm. It was diagnosed by our vet via a stool sample that we took in when we noticed our rooster coughing larval looking things up. Luckily none of our flock had progressed to the gaping.
Here's what she gave us:
Panacur. It's looks like thick milk.
100 mg/ml (100 milligrams of the drug per 1 milliliter of solution)
Dose each chicken with .25 ml per pound of body weight. She gave us one of those little TB/insulin syringes with .25 ml marks. They hold 1 ml total.
Do it for 5 days. In 2 weeks do it again for 5 days.
She said if your chicken weighs 3.6 pounds to round up to 4 lbs. That would be giving that chicken 1 ml of the solution. Its safe, so that's why you can round up to make sure the chicken gets enough of the medication. In the UK they give much larger doses.
We had one chicken that looked poorly after her 2nd dose. We went ahead and continued to dose her and she was just fine the next day. I don't think you should skip a day. You want those parasites dead. I wondered about skipping a day, too, but decided we needed to keep up the treatment. It is true that some of the chickens will die from the dead parasites. That's a risk you must take. Thank goodness we spend a lot of time with our chickens and saw the problem early.
Hope that helps.
