Because they like to look their best.
Although intermittently annoying (yesterday, one of the little devils tried to snatch a sandwich out of my hand while I was standing at the back door), the turkeys have a certain charm. Now that the Dry is here, they are making the most of the opportunity to bathe in the dust and sun.
Dust bathing birds excavate a nice turkey-sized hollow in the soil and then use their wings to scoop dust onto their backs.
When it's time to move, they will stand up and shake themselves like a wet dog to get rid of the excess. As with the soggy pooch, It's not a good idea to be standing nearby when this happens.
As well as getting dust in the feathers, they also like to rub their necks on the soil.
Catching the midday rays is another favourite turkey pasttime. How it's done appears to depend on how secure the bird feels. Most often, they'll just plonk themselves down in a sunny spot and lean a bit to one side so they can catch the sun on the tum.
If there's no one looking, a turkey will roll onto its back to get the full benefit.
Although this behaviour is not without its hazards. This turkey decided to roll over on a downward slope. I don't have the next shot, but you can imagine the feathery panic as gravity took over.
At least when they're doing this, they aren't trying to steal my lunch.