My family had a black and tan rat terrier (formally, a Toy Manchester Terrier) when we were kids. It was smart as a whip, energetic, and with a great personality. My mother even trained it to get my two younger brothers up in the morning on command.
I worked at a chicken farm in South Jersey in the early 1970s. Every once in a while the owner would have a old buddy bring his Rat Terriers around to sniff out and chew up rats. We would follow them around and help them flush out the vermin. Great times!