We have a 5 month old chihuahua, he used to be really good at not barking. My husband works shift work and is sometimes away for a couple weeks at a time. This last time when he came back, our dog, Cooper, has been barking at him almost every time my husband walks in the room. I don't think it's because he doesn't remember him, maybe it's because Cooper thinks he should protect me??? I am not sure. If anyone has any suggestions on how to control this problem, I would appreciate it! Thanks!