Orphaned

For the last few months, up the hill, there's been a lot of lambs generally having a pretty good time with each other and with their mothers nearby if they feel bothered.
Early this morning I came across this dead ewe. There was no sign of wound or injury I could see. A minute or so later, the lamb came out of the bracken, sniffed the body, and stood there looking at me.
It took me a while to find a farmer who knew who the owner was to tell him. The farmer I spoke to said he called it 'sheep's disease', when adults just keel over and die.