I think that dog looks adorable! I had terriers no problem with my chickens, they knew what was part of the family and what was fair hunting game. They are very smart dogs, and yes, require a lot of training, but really aim to please! much more than my current weim/husky mix...
Go visit the dog if you can, and see how she acts. I would ask if you can try her around a cat to see how she behaves. If she tries to chase and you correct her and she stops she will likely be very trainable, if just curious, that is a very good sign that you can teach her to respect small animals, and if she tries to chase and ignores you, that might be a problem! Get her out and play with her for over 30 minutes. It takes shelter dogs about 30 minutes to really settle down and act more like the dog they really are. Play fetch with her, see how interested she is in you, and you will know if she will fit with the family! And I think it's great that you are looking at shelter dogs!!