Eggs Emergencies/Illness

What’s Up With Egg Withdrawal Periods?

I have a few pet peeves: one of them is the misuse of antibiotics and medications and another is folks giving well-meaning, but misguided, advice. Facebook farm groups are full of both.

With the increasingly popularity of small flock chickens we’re also seeing a greater interest and commitment to treating them for a host of illnesses. I applaud folks who care about the welfare of their birds, but it often means obtaining a diagnosis without training or real understanding about chicken illnesses and the drugs used to treat them.

If I had a dollar for every time I saw people advising the use of antibiotics and other medications – some of which are not considered safe for use in chickens, and others outright banned – I’d be rich. I understand the desire to help fellow chicken keepers in crisis, but we are often doing them, and their birds, a disservice.

For every member who posts symptoms of their sick chicken there are numerous responses offering diagnoses, treatment regimens and pharmaceutical remedies –  often conflicting and confusing. The last thing a vulnerable bird needs is to be given  everything but the kitchen sink: vitamins, wormers, dusting powder, apple cider vinegar and/or antibiotics, with the hope that perhaps one of those remedies might be effective.

I also recognize that health issues often occur at inopportune times (late at night or on the weekend) and many people don’t have easy access to, or can’t afford, an avian veterinarian.

I have to admit that I’m also guilty about offering my two cents in a gesture of trying to help. Before I write about health issues or recommend a course of action I endeavour to get that information from reliable sources (i.e. Poultry DVM). I also suggest that folks obtain a correct diagnosis and treatment plan from someone with medical training and know-how.

I think the resistance to consulting with a professional or following regulations runs deeper than cost or availability of trained vets. There seems to be a feeling that the government, in trying to regulate pharmaceuticals, is acting as Big Brother taking away our decision-making rights and our access to products that used to be available in feed stores.

Many folks are upset by the limiting of poultry medications – ones they’ve previously used and know might help their flock. Just because a product works doesn’t mean that there aren’t health risks involved with its use – and often in practice, misuse. Medications need to be used properly (for the right diagnosis, the correct dosage and the full regimen) or our birds can also develop resistance to the drugs that might help them.

There are good reasons for limiting access and setting guidelines for various veterinary drugs. When we overuse or misuse pesticides, wormers, antibiotics and other medications pathogens can develop resistance to those products in future. It also goes beyond the health issues of our livestock to the bigger picture of human health.

Drug Residues

When drugs are given to animals a small part of the drug ends up in their meat, milk and eggs, which gradually dissipates over time. Medications given to a hen means her ovary, follicles and oviduct have been exposed to that drug, and there is the potential for drug residues in her eggs.

Understanding how an egg is made will give you some insight into how, and where, drug residues are most likely to occur. Medications can be deposited in either the albumen (white) or yolk. The albumen in an egg is produced within 24 hours after ovulation so the potential for persistent drug residue is less than that for the yolk, which can be exposed to drugs for longer as it develops over several weeks.

Ingesting drug residues can lead to allergies, cancers, antibiotic resistance and other negative health impacts. If people develop antibiotic resistance then resistant bacteria in humans can cause diseases which are difficult to treat.

Withdrawal Periods

The withdrawal period is the time between when the last dose of a drug was given and when the level of drug residues in the meat, milk or eggs falls below the maximum allowable limit. A livestock animal or its products are not considered entirely safe for human consumption during the withdrawal period.

Many drugs are recommended for use in some species (e.g. cattle sheep, goats) but not others (i.e. chickens). That doesn’t necessarily mean they’re ineffective or unsafe for use in chickens, just that they haven’t been studied and if used on birds would be referred to as ‘off-label’. Generally those products would have little or no data on optimal dosages and side-effects, as well as safety and withdrawal periods for chickens.

Some of these recommended periods are probably longer than necessary, but err on the side of caution.

Various countries have their own rules about approved products and withdrawal periods.

Withdrawal Period
Common Egg Withdrawal Times in North America

Approved Products for Laying Hens

  • Amprolium (Corid): no withdrawal
  • Oxytetracycline in water (800mg dose): 14 days for personal consumption; 8 weeks for sold eggs (approved in Canada, not USA)
  • Permethrin (Permectrin II, ProZap): no withdrawal
  • Piperazine (Wazine) no withdrawal; approved in Canada and Australia, not in USA
  • Spinosad (Elector PSP): no withdrawal
  • Tylosin orally: no withdrawal
  • Tylosin injectable (Tylan): recommended 8 weeks due to lack of studies

Not Approved (allowed only by veterinary prescription, even when available over-the-counter)

  • Ivermectin: not established, recommended 7 days
  • Piperazine (Wazine): no withdrawal (approved in Canada and Australia, not in USA)
  • Oxytetracycline in water (800mg dose): 14 days for personal consumption; 8 weeks for sold eggs (approved in Canada, not USA)
  • Tetracycline in water (Duramycin 10): 14 days; 8 weeks for sold eggs
  • Sulfamethazine (Sulmet): 21 days
  • Sulfadimethoxine (Albon): 21 days
  • Levamisole (Prohibit): 21 days
  • Albendazole (Valbazen): 14 days
  • Fenbendazole (Safe Guard, Panacur)  Not approved in Canada, approved in the USA, UK & EU
  • Pyrantel: recommended 8 weeks due to lack of studies

Strictly Prohibited (Lifetime Withdrawal)

  • BluKote Antifungal Spray (recalled in Canada as of June 2019, no information on withdrawal period)
  • Carbaryl (Sevin)
  • Fipronil (Frontline)
  • Fluoroquinolones (Baytril, Cipro)
  • Metronidazole (Flagyl) and other drugs in this family (Nitroimidazoles)
  • Antivirals

Remember that all pesticides, wormers, medications and antibiotics have some negative health impacts on our birds. Use them properly and prudently.

Some products can be purchased through your vet or local feed store. Here’s a link to a local resource: Veterinary Meds and Farm Supply BC provides licensed sales of livestock health care non-prescription medications, vitamins, supplements and natural products. Canada-wide shipping from Nanaimo B.C.


17 comments on “What’s Up With Egg Withdrawal Periods?

  1. Thank you so much for all the useful information. Poultry DVM and your article is a wonderful help. We will be first time chicken parents next week and excitement and nervousness are mixed together! :)Jen

    Liked by 1 person

  2. Great article. I wasn’t aware of Poultry DVM so thanks for that.

    Liked by 1 person

  3. This one is totally worth a read! Includes hard to find info and answers many questions on this subject. Thanks Claire for sharing your knowledge on many poultry related issues!

    Liked by 1 person

  4. Marcin Nowak

    Excellent read. I would add Elektor PSP to the list that includes Withdraw Period as it seems to be frequently used mites treatment,

    Liked by 1 person

  5. kittyxo101

    Thank you so much for this valuable information I will do some research through the DVM also.
    I honestly had very minimal clue on withholding periods so thanks again xx

    Liked by 1 person

  6. So what are you doing with chickens that you have previously treated with blu kote? US chicken lady here who has used blu kote just for pecking twice in total…(it says on their website that it can be used for that)

    Liked by 1 person

    • Some countries have different rules for the same products. BluKote was pulled from use in chickens in Canada as of July 2019. It is primarily used as an anti-fungal. You can use Stop Pick or Pine Tar to discourage pecking.


      • Thanks for the quick response! Would you still use the chickens for eggs though (since there was no withdrawal stated)? I did reach out to the manufacturer as well but just educating myself!

        Liked by 1 person

  7. Carol Reynolds Johnson

    Thanks for teaching us about withholding times. Why is there no withholding time for Tylan? Should we withhold anyway? I just ended a treatment of tylan in the water of my small flock of 12 that free range, and dewormed with fenbendazole after a fecal analysis, all prescribed by my veterinarian. I know about the withholding time for the fenbendazole but I’m curious now about other meds. Also, some reading I have done suggests these hens are no longer considered organic egg producers. Is that correct? Thank you.

    Liked by 1 person

    • I’m not sure why there are recommended withholding periods for some antibiotics and not others, but I’ll do a little digging to find out. And yes, if you give your hens non-organic feed or antibiotics their eggs are no longer considered ‘certified organic’.



    I’m confused! I was told withdrawal time was when they started antibiotic and so many days after last dose! My chicken is being treated for infection from bumblefoot!
    She was put on Clavamox for infection and Meloxicam for pain! So what is the withdrawal period??

    Liked by 1 person

    • The withdrawal period includes the entire duration a bird has been treated PLUS the stated withdrawal period (i.e. if your bird was on a medication for 7 days and the withdrawal period was 14 days, the true withdrawal period is 7 + 14 = 21.) If your bird has two rounds of a med then you need to factor in a withdrawal period that includes both periods.


  9. So, have treated hens w/ivermectin, cannot use eggs for 10 days i have been told. What do I do with those eggs for 10 days other than toss them in the garbage?

    Liked by 1 person

    • My avian vet told me I could eat them, but shouldn’t sell them so that’s what I do. If you don’t want to do that you can hard boil or scramble them and feed them back to your chickens or your dog. Withdrawal periods are about preventing resistance, not about toxicity or potential harm from ingesting the eggs. In this case, it’s unlikely I’ll ever get round worms or need to use Ivermectin.


  10. Jennifer

    Hi! I’m not sure if this is where I need to ask this question but…I found this article when searching about my situation. My husband had our yard around the house sprayed with Prodiamine that has a grazing restriction. My chickens are free range and will make a loop around my house each evening before they go to their coop. I had them put up for 5 days waiting for it to rain then dry in order for the chickens to be safe. I called the manufacturer about this. They said the chickens would be good but to not eat the eggs for 60 days. My question. It’s been two weeks, could I hatch these eggs or will the chicks have issues?

    Liked by 1 person

    • I did a scan of the product and I wouldn’t want to definitively say that it would be problematic or not, but my guess is there is greater concern for eating the eggs or meat than hatching the eggs. If it were me I would use their eggs for hatching. In future, maybe use a product that isn’t an issue for your household pets/chickens.


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