Day 5 of egg incubation

The chicken eggs have been incubating for 5 days now. The sample set of 5 eggs weighed 291g at the beginning and now weigh 279. A loss of 12g as water evaporates from the eggs. Over 20 days they should lose between 32 and 37g (11-13%) but at the current rate they will lose 48g. If they don’t lose enough weight the chick drowns as it hatches, if they lose too much the chick is shrink wrapped in the membrane inside the shell and can’t hatch! 

I have added some water to up the humidity and slow the rate of loss...  On the outside the eggs look just the same as when they started, but inside you can see a little blob less than a cm across with veins coming out of it. The little blob moves a bit, it has started growing a heart, a spine, a nervous system, eyes, ears, nose, legs, wings and a tongue. It was during day 5 that reproductive organs and differentiation between the sexes started. It will soon start on beak, feathers and claws. A few haven’t grown - there can be a number of reasons, the egg isn’t fertilised, the genetics just aren’t viable, there is something wrong with the egg itself...

You can see the little blob and veins.