I think the problem arises from our extension people telling sheep producers we needed to jug these lambs and their mothers. Following this advise, breeders in the US have managed to either greatly reduce or eliminate the mothering instinct of ewes, thus requiring the ewes to be jugged. This is also translated to going from that kind of lambing environment to a pasture lambing situation, most ewes will not make that kind of transition. Having pasture lambed for 15 years, we had to bring the drop band in this year when the weather dropped to -16F, we had no facilities, so took the hay barn, which was by then 2/3 empty, used 3x4x8 straw bales to make walls. We brought about 90 ewes into an area about 16x60 and went to bed. In the morning we let out every one but the ewes that had lambed. We had to do this for several days. lambed about 75 ewes this way, until the weather improved, no mis-mothering, no problems, but these sheep don't know what a jug is and still have their mothering instincts. All sheep started with natural instincts for lots of traits that we as shepards have managed to change.