Let's start with a new way of thinking...
To get these points across, the first thing we have to deal with is a series of thoughts that I hear expressed all the time.
They go something like this...
"Well, a chicken doesn't..." or "But, when a chicken is sitting on eggs..." or "A chicken doesn't (fill in the space) when she's (fill in the space)".
The easiest way to get over this line of thinking is with two simple facts.
Fact #1
You are not a chicken.
Fact #2
An incubator is not a chicken.
Now that we've got that out of the way, I'm going to take a minute to type the very little I know about sanitation in hatching eggs.
A Little About "Clean"...
Birds are not clean in our sense of the word, nor do they need be to hatch eggs. They have the God given necessities and instinct to get it right every time. The only way it can go awry is for us to stick our noses in and try to help out. Our influence in their environment can easily assure that they never hatch an egg.
Something as simple as the bedding we provide for a nesting hen can destroy any chance she has of successfully hatching chicks.
We've already covered the fact that we aren't chickens, and most of us would be happy to admit that without the aid of machines or tools, we're not likely to incubate an egg to term. There's the occasional story that floats by about the lady who hatched an egg in her bra. Didn't happen, sorry. Cute story though. Not even a bad idea, from an entertainment standpoint.
We're going to have to use tools to get the job done. We're also going to have to prepare the eggs so that they can survive the tools we're going to use.
Any of the tools we use, if we're going to be successful, will provide heat and humidity. We should know (if we were paying any attention to our science teacher) that a hot and humid environment promotes bacterial growth. The toothpaste commercials have covered that too, so even if you watch any amount of TV you should have picked that up.
We have no use for bacteria in the process of incubation. It makes things stink, robs oxygen, and can stifle or destroy incubation.
We need to keep bacteria out of the loop if we're going to be successful.
How do we do it?
We start by washing our hatching eggs. At our house, we wash in 100 degree water with an antibacterial soap (plain old antibacterial dish soap most of the time), then rinse in 110 degree water. The eggs should never be submerged for more than 20 seconds. Soaking eggs for a long time to loosen the bad stuff is a bad idea.
We wash our incubators. We use plain old antibacterial dish soap and hot water.
We wash our hands before and after handling eggs to be used for hatching. I use whatever's sitting there for me to wash my hands with. Hand soap isn't my department so I don't complain about what's sitting there, even if I don't like the smell. The berry-berry stuff really bothers me. The kid stuff that squirts out like foam drives me crazy too, but I'm not complaining.
Once everything is clean, it all starts collecting bacteria immediately. We can't help that, it's life. What we can do is to minimize the amount of bacteria on our stuff.
To do that, I use Brinsea Incubation Disinfectant in a big old squirt bottle mixed exactly like they tell me. There's a lot of different types of disinfectants out there. For lots of years I used Tek-Trol. It worked great, but it was so harsh on my lungs, I hated using it. Because of that, I used it very sparingly. Because I used it very sparingly I had marginal results. The Brinsea doesn't tear at my lungs, it smells pretty, and it's actually a pleasure to use.
Back to how we do it....
I've already cleaned all my equipment, eggs and hands. Once I set all the eggs in the incubator, everything gets misted with my spray bottle. The eggs, trays, and inside of the incubator all get equal treatment.
After a few days I'll take a little sniff to see how things are going. If I can smell anything but clean warm air, I know there's a problem. Bacteria is growing. At this point, all I need to do is sniff the eggs individually to see where the bad one is. Out it goes and I'm back on track. A quick mist of the eggs and inside of the incubator is in order at this point so that I can get back to incubating with as little bacteria as humanly possible.
Working with eggs you've gathered and cared for, you will very seldomly come across a bad egg. If you've set eggs that came from somewhere else, especially through the mail, you'll need to be on your toes.
Eggs don't just go bad.
The inside of a hatching egg is a perfectly sterile environment. It's absolutely devoid of bacteria. The only way for an egg to spoil is for bacteria to enter from the outside. They are built so that can't happen, protected by two membranes right inside the shell's surface. If the membranes are compromised in any way, bacteria can march in and take over.
If we gather eggs and are careful to protect the membranes from harm, we've protected the egg's chance of hatching provided it's fertile and viable* (see footnote). If it's been out of our hands at any point, you can bet "the other guy" isn't caring for the egg the way we'd like him to.
What about the "bloom"?
I knew you'd ask, so here it is. The bloom exists. It's a mucal coating that the hen lays on the egg when it's passing through her reproductive tract. It aids in the egg's movement through the tract and dries to a shiny coating once it's been laid. It provides a neat little barrier so that certain things can't get to the pores of the egg. It deters bacteria from entering the egg by slowing it down. The bloom, in essence, helps protect the egg from bacterial invasion because bacteria has to chew it's way through it before it can reach the good stuff. It's merely a front line of defense. The internal membranes are what keeps the bacteria out through mechanical action (bacteria are to large to get through the membrane's microscopic holes). The bloom is not critical or even necessary for the egg to hatch.
More about the misting...
Too much of a good thing is a bad thing. I may mist eggs once or twice across the course of incubating. Most times I never use the bottle after setting the eggs, nor should I. After the first couple weeks of incubation, misting is a bad idea because it can literally suffocate the chick.
Frequency depends on where the eggs came from, how soiled they were initially, and whether or not any eggs went bad during the course of incubation. If you don't need it, don't use it.
Bacteria is strong in numbers.
As we decrease the amount of bacteria in our incubators, we increase our odds for success. We can't keep it out all together, nor do we need to. A good rule of thumb is that if something smells bad in my incubator, it's bad.
Last but not least...
You know that guy that told you not to wash eggs? He's not a chicken. If his incubator is a chicken, he's absolutely right. If his incubator is not a chicken, refer back to Fact #1.
*Footnote: When an egg is not fertilized, it is said to be infertile. When an egg is fertilized, then rendered infertile by internal and/or external damage, it's said to be inviable.
