Sometimes it is not often we get to see our horses laying down, let alone sleeping. Kat does eithrer one as it pleases him. Life as it should be. 
The other day the turnouts were all in use so I couldn't put mine out while I cleaned stalls. As I worked on my mare's stall, I noticed he kept laying down. He's not one to colic so I kept an eye on him just in case. Knock on wood, my little man has not colicked once in the 20 years I've had him and yes that sounds weird that I have had him that long. 
He would lay there for a while, get up and adjust his position and then lay down again for another 5 minute power nap. At one point he was completely flat out on his side. I tried to get a pic of that but he heard me fidgeting with my phone and moved so I didn't get the shot. 
But obviously it wasn't long before his eyes closed and he was right back out again. He's one of those ponies that if he could, I swear he would snore and it would be cute if he did. He's got such a fun personality. 