I'm sorry this happened, but its certainly no reason to put her down. Train Train and Retrain. She is just around 2 now isn't she? She is entering her rebelious stage probably. Even the most well trained dogs have set backs around this time.

Have you ever watched the Dog Whisperer? I only ask because this Friday he is going to have an episode on about a familys lab eating thier chickens. It might give you some tips. He is really amazing. He really shows that even the most agressive dog can still be rehibilitated.