Isn't that just like a terrier?! She looks like she is at least part Westie to me. Either way I can just imagine my girl going after a snake if she saw one.
Our back yard borders on a tree line that is the edge of a large wooded area. We have some plants that go along the edge of the tree line that I always keep her away from because I don't know what could be lurking in there. Don't want to find out either!
Copper Heads are known to be in this area though not very common. I'm not taking any chances.