Older lab get extra twitchy at night. I used to all my dogs night time movements howling twitching running sucking growling etc but Moos developed galloping and leaping out of bed. Shes asleep twitching or running then she just gets up and stands up almost like a jump. She clearly doesn't know where she is and looks surprised then gets back into bed and is asleep again in seconds. She's just so funny nothing she does is ever just average. Funny little bear
It was quite unerving at first but I've got used to it now. Its on a Parr with sitting up and doing eerie howling at 2am. Freaky dog
Beattie does this too. She really ‘runs’. Apparently it’s just dreaming when they are on a very deep sleep. I was told not to wake her. We might do it too. Who knows?
My Lucius will stick his tongue out while he sleeps and suckles. Once he was asleep on the armchair and started the loudest barking I've heard from him while he was sleeping. He was wagging his tail so hoping it was a nice dream. He also will twitch his eyelids, sometimes open them but you know he's still asleep as he's looking straight through you doing that little woof in his sleep.
The article linked might be of some interest. https://www.psychologytoday.com/au/blog/canine-corner/201010/do-dogs-dream