About the incubator....they usually do need a little adjustment after adding eggs. You can put in some non fertile eggs when you are setting it up and as you get the eggs you want, you replace one for one. The temp won't flux as much that way. But like mentioned already, low temps don't harm as much unless it is really low for an extended amount of time. Mama chickens do have to go out to eat and drink every once in a while....even when they are broody. The smart ones do at least! And the sterilizing the eggs before hatching is for bacteria and disease control. The temps in an incubator are perfect for ickies to grow....but the eggs don't have to be pristine to hatch. After all, most chickens can't keep all the poop and dirt off their feet when the set. And they set in the dirt and other inconvenient places and still have eggs hatch and healthy chicks. I also sanitize the incubator when I am done with a hatch....but I can't when I stagger hatches too much, so I do it a few times a year, but I have to plan it into my hatching schedule.