...but it's important to raise the BAA!
Sheep don't sleep on their backs, so if you happen to see one in this position you should move fast. That sheep is close to death.
When you're training a sheepdog you can sometimes be surprised by a sheep's agility, but they aren't designed to lie on their backs, and they're not good at righting themselves.
A sheep with a heavy, possibly wet, fleece, or that is heavily pregnant or fat (resulting in a broad, flat back) is most at risk of becoming stuck if it rolls over.
It may have been resting, or it may have tried to scratch an itch, but it certainly won't have got itself into that position on purpose.
A sheep stuck on its back is vulnerable for a variety of reasons: not only is it easy prey for crows or badgers, but its own biology is against it.
In order to digest grass, sheep (and cows) have a four-chambered stomach. The largest chamber is the rumen, where the fibrous food ferments. Fermentation produces gas, and when the sheep is the wrong way up the gas can't escape.
The gas builds up, and causes pressure on the sheep's lungs until it simply can't breathe anymore.
The scenario of a combination of suffocation and predator attack is pretty grim, but it's easy to avoid. Keep aware for an upturned sheep when you're out and about, and act quickly if you see one. DO leave your dog at a distance from the sheep if you possibly can, and DON'T worry about taking hold of a good handful of fleece to get the sheep turned over. Whatever evolutionary advantages sheep might have, they don't have convenient handles!
Watch the video above, to find out how easy it is to rescue a sheep which is stranded on its back, then share this page so that others will see how to do it too.