What makes a good treat for a sheep that will get them to come to you. I've gotten cattle and a donkey to come to various vegetables, but these ewes seem to be disinterested in anything that isn't growing weeds. One understands grain, but the other just looks at me. Its lamb comes anytime it thinks I might have a bottle in my hand. These aren't real wild, but I'd like to be able to get then to come to me if I need to.