I'd never really thought about this before. I went out to the barn tonight and when I got there Lucas was laying on his side, groaning loudly, and kicking his back legs (you know how dogs do when they are dreaming? Like that.) Scared the you-know-what out of me because my first thought was he was colicking. I called his name a few times and clucked at him and got no response for a minute. At that point I'm panicing a bit and wondering if I should go up to the BO's house or call the vet or my trainer, no idea what to do. I called his name again and he pops up (as quick as a horse can pop up) and looks at me like I've scared him. At that point I figured he'd been sleeping (I hadn't been able to tell if his eyes were open or not). I watched him for a few minutes and he did his usual grumpy ears pinned nipping at me routine. Now that I'm home I'm a bit worried that something might have been wrong... Do horses dream like dogs do and move around like that?