How do they know?

There are a lot of technical problems with this picture. I've been trying to get a shot of the chickens when they are taking a dust bath, but it's hard to sneak up on dustbathing chickens, especially when a large dog insists on shadowing you.

They keep running away when I get close. Like some people, I guess chickens feel vulnerable in their bath. (Did they see Psycho too?)

So for now all I have is this problematic picture, too dark in one part and too light in another, distracting bits of wood that the dog's dragged into the area, and a picnic table sticking out in one corner. Sorry.

If you'd never seen birds taking a dust bath, you might think that they had gone nuts.

If there is no loose dirt available, they'll dig it up themselves (no lawn is safe).

They alternately flatten themselves in the dirt, and roll over onto their sides in it. They wriggle in it and use their wings to throw it up onto their backs. All while fluffing themselves up so that the dust can reach every feather.

When they've gotten enough dust on them, they stand up and shake it all off. Sometimes it seems like there's enough dirt in there to make a whole other chicken.

I've read that taking a dust bath helps with feather maintenance (absorbs excess oil) and keeps bugs away. Wild birds do it too.

But these chickens never knew a mother or an elder hen or rooster, having been born in incubators and shipped from the hatchery when they were just hours old.

So how do they know to take a dust bath?

Maybe it's hard-wired in their brains, a little instruction somewhere on the DNA.

Or maybe it's just obvious to them. Thirsty, drink water. Itchy, take a dust bath. Just one of the things that chickens are born knowing?