Chicken Worming Guide

Parasites can build up quietly and cause issues like weight loss, poor egg production, weakness, and even death. They also stress the immune system, making birds more vulnerable to other infections.

Regular worming is one of the simplest, most effective ways to protect your flock and support their long-term wellbeing. This guide is designed to be as simple and practical as possible, giving you a clear overview to make confident decisions.

Worming doesn’t have to be complicated, but it does need to be done right. Let’s get started.

If you would like a PDF version of this guide, you can find it below

Download Worming PDF

A Few Quick Things to Note

Worms aren’t always visible.

Many internal parasites can’t be seen with the naked eye—just because you don’t see them doesn’t mean they aren’t there.

Fecal egg counts (FECs) are recommended.

These tests help identify the specific worm species present (if any), allowing you to choose the most effective treatment.

Prophylactic worming should be regular.

If you choose to worm preventatively, aim to treat your flock 4 to 6 times per year, spaced out appropriately. Remember to rotate your wormers so that you cover both round and tape worm.

No wormer is perfect.

Each product varies in flavour, coverage, treatment duration, withholding periods, and method of administration. Take these into account when choosing a worming approach.

One off doses don't cut it

Some worms are stubborn. Certain species, like Capillaria, require multi-day treatments and are more difficult to eliminate. Tapeworm require a one off treatment every 6-8 weeks for up to 2 year depending on your range! Not all wormers are equally effective for every type.

ACV and garlic are not wormers

Apple cider vinegar and garlic are often promoted as natural wormers, but they don’t kill or eliminate worms. While they may support gut health and help create a less friendly environment for parasites, they should never replace proper worming treatments.

Understanding Wormers

On-label vs Off-label Use

On-label use: Following the product instructions exactly (species, dose, method, frequency).

Off-label use: Using the product outside those instructions (e.g. cattle wormers for chickens).

mg (milligrams) vs ml (millilitres).

This is a common and dangerous mistake.

mg = amount of active ingredient

ml = volume of liquid

Trade Name vs Active Ingredient

Trade name = The brand or product name on the label (e.g. Aviverm, Flubenol, Panacur)
Active ingredient = The actual chemical that does the work (e.g. Levamisole, Flubendazole, Fenbendazole)

Active Dose Rates and information

Fenbendazole

Active: Fenbendazole

Trade Name: Panacur 100 and Safe-Guard® AquaSol

Dose: 20–50 mg/kg

Treatment: Administer orally or add to the flock’s only drinking water source.

Withholds:

  • Egg: 10 days
  • Meat: 63 days

Notes:

  • Broad-spectrum; does not cover tapeworms well.
  • Not registered in New Zealand.

Flubendazole

Active: Flubendazole

Trade Name: Fubanol and Flubavet

Dose:

  • 20–30 mg/kg (standard)
  • 60 mg/kg (with tapeworm coverage)

Treatment: Formulated for use in commercial feed production. While it can be mixed manually into feed, this often results in uneven distribution and reduced efficacy.

Withholds:

  • Egg: 0 days
  • Meat: 0 days

Notes:

  • Broad-spectrum wormer.
  • Manual mixing onto feed often leads to uneven distribution and reduced efficacy. A follow-up faecal egg count two weeks after treatment is recommended to confirm effectiveness.
  • On label, Both products are registered for use on chickens in New Zealand.

Ivermectin

Active: Ivermectin

Trade Name: Ivermec

Dose: 0.2 mg/kg

Treatment: Administer orally or topically.

Withholds:

  • Egg: 10 days
  • Meat: 63 days

Notes:

  • Effective against mites and lice.
  • Topical treatments aren't as effective as oral ones.
  • Narrow safety margin.
  • Is not effective against tapeworms.
  • Off label in New Zealand.

Levamisole

Active: Levamisole

Trade Name: Aviverm

Dose: 20–36 mg/kg

Treatment: Administer orally or add to the flock’s only drinking water source.

Withholds:

  • Egg: 7 days
  • Meat: 7 days

Notes:

  • Broad-spectrum; does not cover tapeworms well.
  • Aviverm can be given orally at 0.1ml per kg of live weight to chickens
  • On label, registered for use on chickens in New Zealand.

Mebendazole

Active: Mebendazole

Trade Name: Vermox and De-worm

Dose: 30 mg/kg

Treatment: Administer tablet orally.

Withholds:

  • Egg: 10 days
  • Meat: 63 days

Notes:

  • Broad-spectrum; does not cover tapeworms well.
  • Off label, Registered in New Zealand for humans.

Moxidectin

Active: Moxidectin

Trade Name: Vetmed (pour on)

Dose: 0.2 mg/kg

Treatment: Administer orally or add to the flock’s only drinking water source.

Withholds:

  • Egg: 10 days
  • Meat: 63 days

Notes:

  • Broad-spectrum; does not cover tapeworms.
  • Off label in New Zealand.

Caution! Many moxidectin-based wormers contain added mineral supplements that may be unsafe for chickens. Always check the full ingredient list before use.

Oxfendazole

Active: Oxfendazole

Trade Name: Bomatak C

Dose: 10 mg/kg

Treatment: Administer orally or add to the flock’s only drinking water source.

Withholds:

  • Egg: 10 days
  • Meat: 63 days

Notes:

  • Broad-spectrum.
  • Off label in New Zealand.

Praziquantel

Active: Praziquantel

Trade Name: Droncit and Wormicide

Dose: 10 mg/kg

Treatment: Administer tablet orally

Withholds:

  • Egg: 10 days
  • Meat: 63 days

Notes:

  • Tapeworm-specific; not effective on roundworms; often combined with other actives.
  • Off label in New Zealand.

Final Tips for Successful Worming

Weigh birds accurately

Medication dosing is based on weight. Guessing can lead to underdosing (ineffective) or overdosing (unsafe). Use a kitchen scale for backyard hens if needed.

Repeat treatments when needed

Most wormers require a second dose 10–14 days later to break the worm life cycle. Missing this step can lead to reinfestation.

Don’t mix wormers blindly

Stick to one active ingredient at a time unless specifically directed by a vet. Combining wormers can cause toxicity or reduce effectiveness.

Rotate worming actives yearly

Repeatedly using the same product can lead to resistance. Rotate between different active ingredients annually.

Check withholding periods

If you're consuming eggs or meat, always follow the egg and meat withdrawal times for each product, especially for off-label meds.

Use clean-up protocols

After worming, clean out bedding, scrub feeders/drinkers, and remove faeces to prevent reinfection from eggs in the environment.

FEC testing is your friend

If in doubt, do a faecal egg count before and after treatment to confirm worm burden and treatment success. It can help you reduce unnecessary worming too.

Keep good records

Note the date, product, dose, and any symptoms for each treatment. This helps you track patterns and avoid over- or under-worming.

Support with good nutrition

A healthy gut helps birds resist parasites. Provide a balanced diet, clean water, and vitamin supplements (like multivitamins or carvacrol supplements).

  • photo of a mcmaster slide for fecal egg counts
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