What happened to him?

Today, I sat down when I got home from work to rest a few minutes and spend time with the dogs before cooking dinner.  Thumper sat by me as he usually does (Lightning was hiding upstairs...not sure why, but maybe I should go check...hmmm).  After a few minutes, he stretched out and fell asleep.  I sat, read some of a book, and enjoyed the quiet.  Then he started whimpering and yelping in his sleep, and his legs were twitching, like he was running.  I wondered what he was dreaming.  The noises he made seemed as if they would come from a scared animal.  I wondered if he was remembering the days before he lived with us...and this thought troubled me.  Thumper was definitely mistreated in his past...among other things, his teeth were damaged when we adopted him, he had bare spots where fur is just beginning to grow back, and the vet/organization had evidence that suggested he had been shot at.  Was his dream of something he experienced?  Is that why he sounded scared and upset as he napped?  He has grown into a sweet, affectionate pet.  If he was having a bad dream of his past life, I hope over time good experiences with us will push those memories away and leave him with sweet dreams.  He is a good dog.  Someone really missed out on a sweet, affectionate pet.  And judging by the way he stalks lizards, squirrels, and ducks, he probably would have been a good hunting dog too.  Their loss, our gain.  :)