Panacur 2.5: (Fenbendazole) It is effective against roundworm and giardia, this is another product that can cause feather abnormalities. Crop dose 0.2 mls/100g of body weight if the bird weighs less than 400grams and 0.1 ml/100 grams in birds weighing more than 400grams.� Repeat dose 12-14 days. Panacur will not kill hairworms. This wormer is the main drench used by aviculturist in NZ for the past 25 years, some bird keepers use nilverm for the follow up treatment in the water to help stop resistance to one type of drench being used. Panacur is a very safe wormer to use, but it may cause problems if used while the bird is in molt.
*I have looked into the concept of using panacur administer to the water and for it to be given over a period of time. The reason why it is administer over a period of 3-5 days in some cases is it appears to be less toxic but more effective especially for treating round worms. Hairworms may be more stubborn and will need to be treated for 7-10 days. The dose for water treatment is 125mg per litre of water and to stir regularly to prevent settling. It may also go in the seed 5ml /1-kilo. Treatment for 5 days and no other types of food to be feed. Dosing for finches 2ml/litre of water for 5 days, and be careful to administer correct dosage.