Why no washing/disinfecting eggs?

[debilorrah]

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People like to argue.

 

[Katy]

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Sure - before I post the studies, let me say that my signature refers to the fact that before this summer I hadn't had poultry for about eight years. Before that I had birds ranging from cockatiels to cayugas every year of my life since I was two. I grew up across the road from a prominent pheasant and waterfowl fancier, figured that everybody had black-necked swans in their backyard. I've personally raised and bred chickens (LF and bantam), ducks (runner and cayuga), geese (Pilgrim and African), guineas, house birds of all types, etc. I don't show poultry, because I have no way to quarantine, but I have shown rabbits, Saanens, horses, and now dogs. I have a biology degree and was the teaching assistant who ran the embryology lab (based on chicken eggs and embryos). 90% of a theology master's, too, though that's not necessarily apropos to the discussion

. So no, I'm not new to this.

Here are the studies:

http://edis.ifas.ufl.edu/ps018 is a very good overview of the reasons for disinfecting
http://www.ncbi.nlm.nih.gov/pubmed/1906612 - using hydrogen peroxide; note that dead embryos were significantly reduced when compared to unwashed eggs
http://www.ncbi.nlm.nih.gov/pubmed/2356172 - using quat; again notice that hatchability is improved over untreated
http://www.ncbi.nlm.nih.gov/pubmed/2196048 - the fact that even touching dry litter contaminated with salmonella contaminates the egg in 60% of UNWASHED eggs; if the eggs have moist contamination (as in touching feces), the rate is 100%
http://www.jstor.org/pss/1592082 - chicks hatching from eggs with salmonella quickly infect the other chicks in the same brooder
http://japr.fass.org/cgi/content/abstract/8/4/499 - bacteria easily penetrate egg shells - note "the natural defenses of the egg are generally not adequate" http://japr.fass.org/cgi/reprint/8/4/499.pdf is the full-text PDF of the same article, and is critical to read through; note that by the time the egg has dried in the nest, whatever it was sitting in has been drawn through the pores already.
http://japr.fass.org/cgi/reprint/3/3/234.pdf - e. coli on hatching eggs; disinfection will improve hatchability
There's a great study by Sparks (1985) called "Bacterial penetration of the recently oviposited shell of hens' eggs" showing that the riskiest time was right after the egg was laid, while it was cooling

And before anybody says that backyard flocks don't have to worry about salmonella, yes they do. Salmonella is everywhere - got chickens? You've got a very high chance of having salmonella bacteria out there. http://www.jstor.org/pss/1592033 is a study that isn't easily available in full-text, but they tested a bunch of flocks and found that 100% of their positive s. pullorum results came from backyard flocks. The commercial flocks also had salmonella, of course, but the backyard birds were far from sterile.

I have, seriously, about a hundred more, but the above are some of the most useful and direct.

I will go thru them when I get some time, I'm at the moment trying to get ready for a CHristmas gathering here on Sunday.

I honestly don't care if someone wants to wash their eggs or not......each to their own. I have good hatches and I don't wash mine......but I also don't set dirty eggs. If they're too dirty to set or eat they go out to my dogs and cats.

My issue with studies is that you can find one to support whichever side of the argument you're on or the method you want to use.....not to mention the results often change from one time period to another. I'd rather hear peoples' experiences that they are currently having in their own hatches and what they do or don't do.

One of the biggest contridictions I see is if the egg is supposedly more than likely contaminated from the moment it's laid...or even before it's laid what sense does it make to wash them? We certainly can't disinfect the inside of the egg.

 

[debilorrah]

Quote:
Sure - before I post the studies, let me say that my signature refers to the fact that before this summer I hadn't had poultry for about eight years. Before that I had birds ranging from cockatiels to cayugas every year of my life since I was two. I grew up across the road from a prominent pheasant and waterfowl fancier, figured that everybody had black-necked swans in their backyard. I've personally raised and bred chickens (LF and bantam), ducks (runner and cayuga), geese (Pilgrim and African), guineas, house birds of all types, etc. I don't show poultry, because I have no way to quarantine, but I have shown rabbits, Saanens, horses, and now dogs. I have a biology degree and was the teaching assistant who ran the embryology lab (based on chicken eggs and embryos). 90% of a theology master's, too, though that's not necessarily apropos to the discussion

. So no, I'm not new to this.

Here are the studies:

http://edis.ifas.ufl.edu/ps018 is a very good overview of the reasons for disinfecting
http://www.ncbi.nlm.nih.gov/pubmed/1906612 - using hydrogen peroxide; note that dead embryos were significantly reduced when compared to unwashed eggs
http://www.ncbi.nlm.nih.gov/pubmed/2356172 - using quat; again notice that hatchability is improved over untreated
http://www.ncbi.nlm.nih.gov/pubmed/2196048 - the fact that even touching dry litter contaminated with salmonella contaminates the egg in 60% of UNWASHED eggs; if the eggs have moist contamination (as in touching feces), the rate is 100%
http://www.jstor.org/pss/1592082 - chicks hatching from eggs with salmonella quickly infect the other chicks in the same brooder
http://japr.fass.org/cgi/content/abstract/8/4/499 - bacteria easily penetrate egg shells - note "the natural defenses of the egg are generally not adequate" http://japr.fass.org/cgi/reprint/8/4/499.pdf is the full-text PDF of the same article, and is critical to read through; note that by the time the egg has dried in the nest, whatever it was sitting in has been drawn through the pores already.
http://japr.fass.org/cgi/reprint/3/3/234.pdf - e. coli on hatching eggs; disinfection will improve hatchability
There's a great study by Sparks (1985) called "Bacterial penetration of the recently oviposited shell of hens' eggs" showing that the riskiest time was right after the egg was laid, while it was cooling

And before anybody says that backyard flocks don't have to worry about salmonella, yes they do. Salmonella is everywhere - got chickens? You've got a very high chance of having salmonella bacteria out there. http://www.jstor.org/pss/1592033 is a study that isn't easily available in full-text, but they tested a bunch of flocks and found that 100% of their positive s. pullorum results came from backyard flocks. The commercial flocks also had salmonella, of course, but the backyard birds were far from sterile.

I have, seriously, about a hundred more, but the above are some of the most useful and direct.

I will go thru them when I get some time, I'm at the moment trying to get ready for a CHristmas gathering here on Sunday.

I honestly don't care if someone wants to wash their eggs or not......each to their own. I have good hatches and I don't wash mine......but I also don't set dirty eggs. If they're too dirty to set or eat they go out to my dogs and cats.

My issue with studies is that you can find one to support whichever side of the argument you're on or the method you want to use.....not to mention the results often change from one time period to another. I'd rather hear peoples' experiences that they are currently having in their own hatches and what they do or don't do.

One of the biggest contridictions I see is if the egg is supposedly more than likely contaminated from the moment it's hatched...or even before it's laid what sense does it make to wash them? We certainly can't disinfect the inside of the egg.

I agree with you. The dirty ones get washed for eating the cleaner ones go in the bator. And as public employee, I can tell you that each and every study out there is shifted toward what they want to prove.

 

[BlacksheepCardigans]

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These are the search parameters I used . You're welcome to make sure I didn't miss any dissenting studies, but I know that hatching eggs have been disinfected for over a hundred years.

There are several steps to the picture - one is always having a clean clean CLEAN and consistently dry surface to lay on. That helps to prevent eggs being contaminated from the bedding. Then you have to prevent the contaminated eggs from spreading the germs to uncontaminated ones, and try to prevent surface-contaminated eggs, which CAN hatch if the bacteria doesn't overwhelm them, from developing bacteria levels that are so high that the embryo is killed. That's where washing and disinfecting come in. You also have to remember the role of heat and moisture, which are also crucial to the contamination killing chicks.

I don't want anybody to think that I'm insisting that all eggs must be washed, or that you won't get acceptable hatches with unwashed eggs. The reason I started this thread is that over and over again I was reading people saying that the egg is sterile as long as you don't wash it, or that you can incubate eggs as dirty as you want, or variations on the theme of the bloom being super ultra perfectly protective from any and all ickiness, so the worst possible thing you can do is wash an egg. And against that I was reading stuff from a hundred years ago all the way up to now, every piece of incubation literature from the old magazines , even in the nineteen-teens and twenties, all the way to now - everything said only set clean eggs and to disinfect to prevent disease. (The link above, by the way, to the Poultry Item, is about preventing coccidia and "brooder pneumonia" - mycoplasma? - by dipping eggs in alcohol, but the whole set of magazines is fantastic and worth exploring.)

In terms of whether studies are unbiased, I honestly think that you can get a really good idea of reliability when you have widespread agreement or when it's supported by disinterested parties. For example, I read a lot of studies on asthma because my daughter has reactive airway disease. If I see a study coming from GlaxoSmithKline saying that inhaled steroids are good for asthma, I am hardly going to go to her doctor and ask for it. When I see that the Will Rogers Institute has a study saying that inhaled steroids are good for asthma, that's a whole different story.

 

[theredroosta]

I just realized nother thing, if you wash all your eggs and disinfect your incubator there really isn't any argument here because the bloom would have no effect in a sterile environment. And bycers could do a study to prove once and for all, whether or not the bloom has any effect. It should be conducted with a few dirty eggs, a few clean washed eggs, and a few clean unwashed eggs. All kept in separate incubators.

 

[BlacksheepCardigans]

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"A few" wouldn't work, unfortunately. You'd have to set hundreds, they'd all have to be from the same breed, they'd all have to be from hens and roosters the same age, they'd all have to be from the same flock (housed in one area), the incubators have to be identical, etc. That's why researchers are always using broiler eggs - they can get vast numbers of eggs with almost no variables. For a study to be reliable, you have to have only one thing change - in this case, whether an egg is washed or unwashed. You can't have anything else be different.

A home hatcher could get some semblance of the same kind of statement of true/untrue over many hatches, months or years of hatches, because after a while the sheer weight of the numbers would overwhelm the problem of the variables. So if you kept good notes you could say "I got a better hatching rate in 2011 than I got in 2010 and I'm pretty sure it was due to X." But you'd have to keep the variables as close to zero as possible. If in 2011 you were hatching a different breed mix or drastically changed your feed milling or started collecting six times a day instead of once, then you couldn't say it was due to washing.

 

[Muggsmagee]

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People like to argue.

Wrong. I can only speak for myself, but I won't settle for one sided studies and assume they pertain to me. I want all factors taken into account, and clearly, they are not. Wash if you want, don't wash if you want. That's what it boils down to.

And I will be going through all of the studies posted...when I have more time. I enjoy them.

 

[iluvsedward]

I rinse mine and my last hatch was 100%

 

[theredroosta]

Quote:
"A few" wouldn't work, unfortunately. You'd have to set hundreds, they'd all have to be from the same breed, they'd all have to be from hens and roosters the same age, they'd all have to be from the same flock (housed in one area), the incubators have to be identical, etc. That's why researchers are always using broiler eggs - they can get vast numbers of eggs with almost no variables. For a study to be reliable, you have to have only one thing change - in this case, whether an egg is washed or unwashed. You can't have anything else be different.

A home hatcher could get some semblance of the same kind of statement of true/untrue over many hatches, months or years of hatches, because after a while the sheer weight of the numbers would overwhelm the problem of the variables. So if you kept good notes you could say "I got a better hatching rate in 2011 than I got in 2010 and I'm pretty sure it was due to X." But you'd have to keep the variables as close to zero as possible. If in 2011 you were hatching a different breed mix or drastically changed your feed milling or started collecting six times a day instead of once, then you couldn't say it was due to washing.

You can scrutinize the variables all you want, but if there's really this many possible issues who's to say that washing has absolutely any effect on egg health? Plus, if you could check for bacteria with an instrument of some sort you wouldn't need to worry about breed, incubator, age, because all you need to know is if there is contamination in the failed eggs. And I don't understand why there has to be hundreds, if in a batch 15 eggs out of 30 hatch that are unwashed and the unwashed dead eggs contained contamination then bacteria and not washing you eggs is responsible for 50% of the deaths. However in a batch of 30 clean eggs 20 hatch and the dead eggs do not contain contamination, then it is safe to say washing them will improve rates. These experiments of course have to be conducted in a sterile environment and in different incubators for the results to be true. And it should be repeated several times after wards to prove the theory. I'm not an idiot, I know how experiments work, the variables don't need to be scrutinized to death, but need to be singled out if possible.

 

[theredroosta]

Quote:
People like to argue.

I love to argue.