Our old dog (is that the correct way to refer to him? "My before dog"?), Yankee, was super active when he slept. We always used to joke that he had to take extra naps to make up for how exhausting his sleep was! He barked. He nursed. He licked his lips. He growled. He wagged his tail. He ran in place. He whimpered. His "eyebrows" danced all around. He flopped back & forth. He kicked. He burped. He wiggled his toes. But he did all this laying down. I've never heard of a dog literally sleep barking, but I'm sure stranger things have happened!