Hello,
We use several different methods of adopting a lamb under a ewe, the first being spraying the lamb with a lovely strong pungent smelling perfume and spraying in front of the ewes nose (not up it). When spraying the lamb its best to spray the underside of it and its rump and this is where the ewe normally smells first.
The second being "skinning" this is where you simply skin the dead lamb and place the skin on the lamb to be adopted,
The third being using a bucket of warm water place the dead lamb into it, this then brings out all its natural smells etc.. then rub the dead lamb all over the adopted lamb, so that the ewe recognises the smell.
All three of these normally work for us!!
Hope this helps
Katy