My one year old Lab/Great Pyrenees has found that she quite enjoys chasing and occasionally killing my chickens. So far she has already gotten three of my hens and has killed two of them. I have always had her come out with me when I take care of the chickens, and when i am around she is always perfectly good. But once i leave she instantly goes after them. so i have started having to tie her up or keep her fenced up, but i just feel so bad not letting her roam free and explore. any ideas? thank you.