The reason I haven't shared my experience (which is: groups that I incubate that include dirty eggs have a much higher death rate in the whole hatch than when I have a group where none of the eggs are dirty) is precisely because the plural of anecdote is not fact. It's kind of like a ton of people saying "I never wore a seatbelt and I'm fine!" Well, yes, obviously you have survived long enough to write that, so anecdotally not wearing a seatbelt is safe. But when you look across the entire spectrum of people driving, not wearing a seatbelt substantially increases your risk of death. Or, another example, I have four daughters and no sons. My anecdotal evidence is that it's much more likely to have girls than boys when you're pregnant. But nobody should trust me if I say that. The reason there's such a thing as studies, and why they're more reliable than anecdotes, is that you have to look at a large group where nothing else could possibly be the issue before you can say something that approaches truth.
I know there's that line - anybody can find studies to prove anything - but it's actually not true. A single study is interesting but not conclusive. A peer-reviewed published study is more interesting but still not actionable. A huge number of studies, showing that the phenomenon is reliable and can be replicated, is where the rubber hits the road.
Using an example from humans, let's say that a company invents a compound that they believe will work as an antidepressant. That company does the initial studies, finds that the compound is more effective than a placebo, and submits those studies to the FDA. At that point a few MDs are probably aware of the new compound but nobody is going to prescribe it yet, because at that point it actually is in the "I am not sure this study is reliable; it may be slanted" stage. They all wait for peer-reviewed published studies from individuals who don't work for the companies. Those come, and still there's going to be very slow/light adoption of the new drug. Then more studies start to pile up, and after maybe ten or twenty, and at least one is a large observational study by individuals who have no connection to the original company, your doctor might say "There's a new drug on the market that looks promising for your type of depression; I'd like you to think about switching." And then, usually a few years after the drug has reached wide adoption, researchers at the NIH or a similar large group will do a massive retrospective study of thousands of people, looking for evidence that the drug really has worked. That massive study is considered the most reliable, and it defines "best practices" for the medical community vis a vis that drug or class of drugs for a few years until they have enough new compounds on the market that they need to do another massive retrospective study.
Ag researchers have been saying that you need to disinfect eggs since 1908. We're past the initial part, past the adoption part, waaaaaaay past the observational and even retrospective parts. Never setting dirty eggs, and disinfecting clean ones, has been considered a best practice for decades. We're LONG past the time when a study would benefit anybody economically; nobody is testing a brand-name disinfectant, and skipping the disinfectant entirely would be cheaper for the big hatchery. I really can't see where any piece of disinfecting has anybody tempted toward wrongdoing and therefore trying to slant studies.
Will you get dirty eggs that hatch - absolutely. Will you get hatch after hatch after hatch at decent rates if you never wash an egg - yes. The question is whether you are OPTIMIZING your hatching rates, getting as high as you can possibly get. The question is whether the advice to never wash is good advice, neutral advice, or bad advice.
Those can't be answered by me and my Brinseas. All I could ever give are anecdotes. Best practices need to be based on reliable and experimentally controlled evidence over years.
Veering slightly away from disinfection, on this board we have anecdotal evidence that hatching eggs on their ends (the "hatching in egg cartons" method) may partially compensate for less than ideal humidity during incubation. I think that's fascinating and it makes very good sense to me, and my current eggs, which are a couple days away from lockdown, are going to hatch upright. But it's still in the "that makes sense" stage; if I have a good result it's still just anecdotal. If I came across fifty studies that all showed that hatchability was much lower in upright eggs, then I have to conclude that my experience with ten eggs is not as reliable as their experience with thirty thousand eggs.
We rely on studies in every other aspect of the way we raise chickens. Studies determine the ingredients and protein content in feed, but we're happy to tell someone that their protein is too low or their calcium content isn't high enough. Studies determine which cross produces the fastest-growing bird, which is why Cornish X are being raised in huge quantities. Studies tell us that dry litter is healthier than wet litter, that leghorns are bad feather-pickers, that low protein leads to cannibalism. All of these we're happy to use to give advice. So why is washing eggs all of a sudden the result of "one-sided studies"?
