Olivia , did it sound like a squeaky dog toy sorta? Both of my chins will make that sound sometimes when they are asleep . I think its a nightmare and I have to go wake them up and comfort them sometimes when they do it alot. Then my dog started to react to it as well and He will run into the room and put his nose to the cage by where they are and whimper a little as if to say "its ok buddy im here" They think he is just a big chinchilla.