I've never washed an egg and I've never had an egg explode in my incubator. In fact, the best hatch I've yet had came from a group of absolutely filthy duck eggs I got from a friend of mine. A batch of shipped eggs came to me washed, and 9 out of 10 I tossed to bacterial infection. So according to my personal experience, I won't be washing eggs.
The reason for not washing eggs is indeed that it can remove the protective bloom on the outside of the egg. Bloom is a coating on the egg that clogs the egg's pores, which helps with preventing bacteria from crossing the shell and reduces moisture loss from the egg. People who wash eggs to clean bacteria may in fact be making their eggs MORE susceptible to bacterial attack if something finds its way into the incubator- and as bacteria grows *everywhere* no matter the sort of cleaning job you may do, it's a safe bet that this can and will happen at some point. Bacteria enjoy incubators just as much as eggs do, as the temp and humidity used during egg incubation is *perfect* for bacteria growth as well. On top of this, the actual act of washing (rubbing or scrubbing) can push/force bacteria through the pores into the eggs, so that now you have a clean, perfectly susceptible egg that is contaminated on the inside and has just as much chance to explode as that dirty egg you picked up. Maybe more, because now your egg has no coating to stop the bacteria from getting back outside the egg and jumping to your other washed eggs.
One of the best reasons (and the ONLY reason, in my opinion) to wash an egg is if you are putting it in with other washed eggs. An unwashed egg put in with washed eggs can result in the washed eggs getting contaminated because their natural protection has been removed.
Major production companies often wash their eggs under the belief that visual cleanliness will improve hatch rates but this belief has no scientific base. A lot of money has gone into finding washing aids/soaps/scrubs/etc that will successfully clear bacteria AND improve hatch-ability but as far as I'm aware none have been capable of the latter. Production companies also wash outgoing eggs to consumers (a good practice) but pre-shipping they 'restore' the bloom by coating the eggs in a layer of edible mineral oil. This protects shipped eggs from catching issues on the way to your home but I do not believe it is used on eggs meant to be hatched. The mineral oil is added so that the shelf life can be extended, otherwise your fridge eggs would go bad rather quickly.
And lastly, there shouldn't be a reason for dirty eggs in the first place. A clean kept facility (in any capacity, the neighbor with a couple laying hens in the garage to the producer will millions of hens) is the first and biggest step to healthy, clean eggs.
If your eggs didn't hatch well, there are any number of other reasons why this might have been, ranging from incubator conditions, time spent lounging at that guy's place before he brought them to market, improper storage before bringing them to market, roosters not doing their jobs, food or water conditions... Chances are the washed or unwashed state of the eggs was not the cause.
THAT BEING SAID. There are some more 'safe' ways to wash eggs if you feel absolutely compelled. I personally still wouldn't recommend it, but here is a nice link to read so you can decide for yourself.
http://www.poultryhelp.com/uc-pfs22.html
Better luck next time if you decide to try again
