The
Committee for Medicinal Products for Veterinary Use assessment report for Panacur AquaSol offers very detailed info on use of fenbendazole for poultry.
From info on page 12, it looks like the dose for treating
large roundworms or
cecal worms should be
1 mg of fenbendazole per kg of bird's body weight, given for 5 days
[which is the same as 0.454 mg of fenbendazole per pound of bird's body weight].
--Side note: 3 kg (6.6 lbs) can be used as a very general weight for a backyard breed hen.
This is also the dose rate specified on the product label itself for
Safe-guard Aquasol dewormer for chickens. [Note: Horses are normally dosed at 5 mg of fenbendazole per 1 kg of horse's body weight.]
Safe-guard 10% liquid goat dewormer
has
100 mg of fenbendazole per 1
mL of liquid. (The bottle contains 125 mL total of liquid.] If being precise, you would give 0.01 mL of liquid for each kg of bird's weight each day.
Safe-guard and Panacur 10% paste horse dewormers
each have
100 mg of fenbendazole per 1
gram of paste and the tube contains a 25 grams total of paste. If being precise, for each kg of your bird's weight you would give 1% of 1/25th of the contents of the tube each day.
Safe-guard Aquasol liquid dewormer (for chickens and pigs)
has
200 mg of fenbendazole per 1
mL of liquid. If being precise, you would give 0.005 mL of liquid for each kg of bird's weight each day.
Bottom line:
You only need a TINY bit for deworming a single chicken.
Fenbendazole has a wide margin of safety, however, so some overdosing is not as risky as with many other medications.
My bird's don't mind eating fenbendazole. Based on my experience and others', I'm thinking it is commonly safe to give a tiny pea-sized amount on a very small piece of bread to each chicken, and that amount is plenty to be effective if you give for 5 days.
[Note:
To treat GAPEWORMS or broad-headed tapeworms,
one study suggests the dose should be 15 to 20 mg fenbendazole per kg of bird's body weight for 3 consecutive days. This would be up to
0.6 mL per day for an average backyard hen.]
I will soon also get this updated on the
Chicken Medicine Chart but wanted to get it posted here.