Our black lab has never, ever, bothered any of our chickens. In fact, one day I watched as he lay in the barn and one of our young pullets hopped up on his back and started pecking dirt off him. I had to shoo the chicken away because she was getting too close to the dogs face for my comfort. I hope it does all work out for your sister. I'm sure with your guidance and knowledge, she too will become a happy chicken keeper!