I finally got around to calculating the amount of Safeguard pellets to use to deworm my flock, and thought I would share it.
Some background:
DON'T USE:
Check the units as you go, if you do the calculation right, your answer will have the right units.
See bracketed text below 1 for an example of how units can show you did it wrong.
Example: 20 hens, each weighing 5 lb
1. Calculate hen's weight in kg
5 lb/hen x kg/2.2 lb = 2.27 kg/hen >round to 3 kg to keep it simple
[If I got this mixed up the units would be wrong: 5 lb hen x 2.2 lb/kg = 11 lb^2/kg]
2. Calculate dose/hen
a. Minimum dose (10 mg/kg) = 3 kg/hen x 10 mg fenbendazole/kg = 30 mg fenbendazole
b. Maximum dose (50 mg/mg) = 3 kg/hen x 50 mg fenbendazole/kg = 150 mg fenbendazole
3. Calculate the dose for the flock
If you have both large and small birds, add up the total weight of the flock (see * below).
However, you can just calculate the dose for the large birds and dial it back a bit.
The small birds eat a lot less, so take they care of the dosage issue.
20 birds in the flock
a. Minimum dose (from step 2a) 30 mg/hen x 20 hens = 600 mg
b. Maximum dose (from step 2b) 150 mg/hen x 20 hens = 3,000 mg
Note - the paper I referenced in "Some background" showed the minimum dose, 10 mg/kg, was effective, so save your pellets.
4. Calculate the amount of feed to give
Amount of fenbendazole in the feed is 2270 mg/lb
a. Minimum dose for the flock = 600 mg (from 3a) x lb/2270 mg = 0.26 lbs >round to 1/4 lb
b. Maximum dose for the flock = 3,000 mg (from 3b) x lb/2270 mg = 1.32 lbs >round to 1 1/3 lb
Mix 1/4 to 1 1/3 lb > choose 1 lb to keep it simple.
Mix it with enough of their regular feed that it takes them a few days to finish it.
That way everybody gets some, and they get the right dose for their weight.
Give this mix as the only food until they finish it, then go back to their regular food.
I DO NOT repeat in 10 days.
Frequent worming with the same agent leads to the wormer not working anymore.
Repeat the worming when clinical signs reappear or see other signs (worms in poop).
*Calculating weight in a flock of different sized birds.
Weigh or look up weights for the different birds in your flock and add them up.
Example flock:
A pair of D'Anver bantams (male and female), 8 Cochin hens, and 5 Maran hens
Weights from table https://farmhouseguide.com/how-much-chickens-weigh/
Good luck!
Some background:
Fenbendazole, the active ingredient in Safeguard Pellets is an antiparasitic drug used to reduce/remove nematode (worms) and protozoal parasites (Giardia, microfilaria). FDA approved fenbendazole for the treatment for roundworms (Ascaria galli) and cecal worms (Heterakis gallinarum) in broiler and breeding chickens. The FDA allows 2.4 ppm fenbendazole in eggs with no withdrawal time from application. www.ams.usda.gov/sites/default/files/media/LSFenbendazoleRec_webpost.pdf
Fenbendazole is on the approved list of Synthetic substances allowed for use in organic livestock production
The common worms in backyard flocks are roundworms (Ascaridia), cecal worms (Heterakis), threadworms (Capillaria), and tapeworms (Raillietina and Choanotaenia). A 2020 paper showed fenbendazole was effective against all these worms in free-range chickens given a single oral dose of 10 mg/kg (Vet Parasitol Reg Stud Reports. 2022 May;30:100723. doi: 10.1016). Note the drug combination used to treat Taenia tapeworms in dogs and horses, praziquantel with pyrantel tartrate, is toxic to chickens!
The goal is to keep these worm populations low, so they don't cause clinical problems, and use wormers infrequently, to keep the worm populations susceptible to treatment. High worm burdens are one of a dozens of causes of diarrhea, depression, weight loss, anemia, and decreased egg production. You only know if worms are the cause by a microscopic exam of poop or by seeing worms in droppings or eggs.
DON'T USE:
- When birds are nesting or molting - it causes deformed feathers.
- On Pigeons/Doves - they are sensitive
- A broad spectrum wormer treats susceptible roundworms (Ascaris), threadworms (Capillaria), caecal worms (Heterakis), gape worms (Syngamus, but not gizzard worms in finches), flukes, microfilaria, Giardia, fowl tapeworms (Raillietina, Choanotaenia) and Ostrich Tapeworm (Houttuynia)
- Amount of fenbendazole in SAFEGUARD Pellets: 2.27 gm/lb = 2270 mg fenbendazole/lb of feed
- Dosage of fenbendazole needed per bird: 10-50 mg/kg bird (works for chickens, ducks, peafowl, guineas, turkeys, etc. For ratites use 15 mg/kg) - from Plumb's Veterinary Drug handbook. Note the wide safety margin.
- Weight of your bird: as @casportpony recommends, you should weigh your birds. For this case, you can look up average weights in tables on the internet and avoid the rodeo.
Check the units as you go, if you do the calculation right, your answer will have the right units.
See bracketed text below 1 for an example of how units can show you did it wrong.
Example: 20 hens, each weighing 5 lb
1. Calculate hen's weight in kg
5 lb/hen x kg/2.2 lb = 2.27 kg/hen >round to 3 kg to keep it simple
[If I got this mixed up the units would be wrong: 5 lb hen x 2.2 lb/kg = 11 lb^2/kg]
2. Calculate dose/hen
a. Minimum dose (10 mg/kg) = 3 kg/hen x 10 mg fenbendazole/kg = 30 mg fenbendazole
b. Maximum dose (50 mg/mg) = 3 kg/hen x 50 mg fenbendazole/kg = 150 mg fenbendazole
3. Calculate the dose for the flock
If you have both large and small birds, add up the total weight of the flock (see * below).
However, you can just calculate the dose for the large birds and dial it back a bit.
The small birds eat a lot less, so take they care of the dosage issue.
20 birds in the flock
a. Minimum dose (from step 2a) 30 mg/hen x 20 hens = 600 mg
b. Maximum dose (from step 2b) 150 mg/hen x 20 hens = 3,000 mg
Note - the paper I referenced in "Some background" showed the minimum dose, 10 mg/kg, was effective, so save your pellets.
4. Calculate the amount of feed to give
Amount of fenbendazole in the feed is 2270 mg/lb
a. Minimum dose for the flock = 600 mg (from 3a) x lb/2270 mg = 0.26 lbs >round to 1/4 lb
b. Maximum dose for the flock = 3,000 mg (from 3b) x lb/2270 mg = 1.32 lbs >round to 1 1/3 lb
Mix 1/4 to 1 1/3 lb > choose 1 lb to keep it simple.
Mix it with enough of their regular feed that it takes them a few days to finish it.
That way everybody gets some, and they get the right dose for their weight.
Give this mix as the only food until they finish it, then go back to their regular food.
I DO NOT repeat in 10 days.
Frequent worming with the same agent leads to the wormer not working anymore.
Repeat the worming when clinical signs reappear or see other signs (worms in poop).
*Calculating weight in a flock of different sized birds.
Weigh or look up weights for the different birds in your flock and add them up.
Example flock:
A pair of D'Anver bantams (male and female), 8 Cochin hens, and 5 Maran hens
Weights from table https://farmhouseguide.com/how-much-chickens-weigh/
- D'Anver M 26 oz (1.6 lb. 0.74 kg) + F 22 oz (1.3 lb, 0.6 kg) = 1.3 kg
- Cochin F 9 lb (4 kg) x 8 hens = 32 kg
- Maran F 4.4 (2 kg) x 5 hens = 10 kg
Good luck!
