How to tell good eggs from bad

Our hens stopped laying in the fall when they molted.  It's so annoying to buy eggs when there's a coop full of chickens in the yard.

When one of the girls started laying again about a week ago I was pretty psyched.  Yesterday Gene brought a second egg into the kitchen and we were both happy because it meant the girls are starting to produce again. 

Eggs, of course, mean spring can't be too far off (ironically I'm writing this post in the middle of a snowstorm).

After I put the new egg with the others Gene confessed that he had found it behind the nesting box, rather than inside of it.  He had no idea how long it had been there.  It could have been laid last summer or yesterday.

There is only one good way to determine an egg's freshness without cracking it open: put it into a glass of water.

Because the membrane and shell of an egg are porous, moisture inside an egg gradually evaporates.  Bad eggs, having lost much of their liquid content, will float. Good eggs will sink, and eggs in between will stand on end of the water.

Or so conventional wisdom says.  I'd never tried this before but the rationale behind it seemed valid.

Here's the questionable egg:

And here's an egg we knew for certain had been laid that day:

We threw that egg away faster than you can say "pee-yew".