This clip shows one of our dogs; Jess, guarding her pet guinea fowl. It may look like she wants to eat him, but she is actually looking after him. The little nips she gives him are a signal to move; herding behaviour. That particular guinea fowl was a sickly chick and so spent a month sleeping in a box by the fire, which is also where Jess sleeps (not in a box, on a mat by the fire), so they must have bonded. She spends her day following him and if he gets into a fight (which he does a lot) she will move in and break it up. When he goes outside the yard where she can’t follow Jess will sit at the gate looking worried until he returns. When he flies up into a tree to sleep at night Jess comes to the door to be let in, she flops down by the fire with a sigh that sounds like the one I give when I get home from work.
Jess has an adult puppy; Val, who also lives with us, but she has never been like that with her own pup. I don’t know if this is frustrated herding/ guardian behaviour or if she has an OCD tendency.