It is awful not knowing the reason, and even more weird that in three of the cases I was away from home. The first casualty was Dixie, one of my favourite Gotlands ewes, she was an adult. This happened in September after I had been in Cornwall for four days - she had been fine when I left. I came back to find her skull and backbone in the field.
The next two casualties were this year's Gotland lambs; a ewe lamb and a wether. Both cases happened in November. There was no skeleton at all of the ewe lamb, just a pile of fleece and the remains of her hind legs. The wether I found whole, with a hole in his side. I took him for a PM but it was inconclusive as he had been scavenged and wasn't fresh.
All the above three had died in roughly the same place, near a badger sett.
The fourth was the Herdwick ram lamb, he was in a small paddock with a Gotland ram lamb. All that was left of him was a pile of fleece, skull and backbone.
All of them except the adult ewe I had not checked them for a day or two as in two instances I had gone away and the most recent I had been ill! So they couldn't have been dead for more than one or two days. With the adult I had been away for four days so she could have died any time then. All of them had been absolutely fine when I checked them last.
My fields are totally stock fenced with metal bar gates. I had not been giving them extra feed as they had enough grass. In fact the sheep I lost had the best grass of all the fields! They had not moved grazing. No other livestock shared the grazing (except now all the ewes are in with the horses as their field is the best drained with a large field shelter). No roofing felt/polystyrene had blown in - I always remove any rubbish I find beit baler twine or bits of plastic bags.
I am going to ask my vet (he used to farm sheep); I've also been trying to ring my neighbour who has sheep grazing on his land but he's been out.