My Tucker is only 11 lbs too, but quite the hunter, even before the chickens he regularly hunted and killed all kinds of rodentia. Our chickens are not free range, they will be in a rotating fenced garden area, and now we added another fence so the dogs have half the yard and the garden/chickens have the other half. Now the dogs can't get near the actual chicken run/garden b/c of the second fence. He is a very sensitive dog about displeasing me so when I am there he is a perfect gentlemen, it is when I am not that is the problem. I work w/ him most every day but seperation is going to be the only solution. I would consider a shock collar reluctantly, but would probably string a hot wire instead if this doesn't work.