My neighbour swears by spraying the lambs, top and tail, with Pledge furniture polish. Sounds hilarious I know but he doesn't seem to lose any. He takes his lambs up to the top field which is very isolated and next to a plantation so lots of cover for foxes, when the lambs are well mothered up at 2-3 days. So the lambs and ewe recognise each other by sound as well as smell by then. I'm surprised really that lambs that age were taken. Here foxes are a real danger during birth, when one lamb is up and the second is being born, so a fox can sneak in and take the firstborn. This is a problem because the ewe has gone off on her own to give birth, so has no mates to help defend the lambs. Once they are older, the ewes all sit in a circle at night, with all the lambs to the inside, and they can give a fox a really good duffing, dogs too.