It's not difficult for me to find confronting sheep...but it is difficult to find ones that won't stomp on your dog. I pretty much have Kilt pick my sheep for Yoko. Today we worked two sheep out in the open, several acres away from the sheep pens. The dog has to have "feel" or they will lose the two sheep. And, many times the two sheep will face off the dog. Yoko is learning to walk in closer. I need to help her understand if she walks in another 18 inches, the sheep will turn. I don't want her to bite unless someone bobs a head at her. Then, game on. The nice thing about Yoko is she won't take her eyes off the sheep facing her. Plus, she gets tall like her mother. I like that.
I also took Yoko to a smaller pen with a lot of grass for 4 sheep to hang out in. Yoko only bit a front foot once. She either took a heel or a nose without much urging. She even tried slinking to the outside of the pen and pushing them with her body a bit. I'd say this is progress. Her mother can push herself in a packed pen and actually go in between legs, etc. She is very comfortable. Yoko needs to sniff, touch, and feel more comfortable. Onward and upward!