We had 4 lambs. One of the ewes had a single lamb, the other had triplets. I'm inexperienced with lambs and sheep in general, so I was watching to see when the lambed, but really don't know what to expect, or what is normal.
With pigs, it's pretty normal to lose a pig or two out of a litter -- they're stillborn or die a few hours after being born. So when I found a dead lamb in the pasture the day they were born I chalked it up to that. But I didn't find the lamb until after a pig had found it (I assumed) and all that I found was the head and spine. The rest was gone. But the other three lambs were fine.
I excluded the pigs from that pasture on general principles -- I don't know if a pig will eat a live lamb, but I don't want to find out, either. So having done that, all looked good and I watched for the next day or two. I was a bit concerned about the interactions between the lambs and the cows, afraid the lambs might get stepped on, but it looked ok.
But today all of the lambs were dead. Click on pictures for bigger versions if you want to see more detail.
died from suffocation, having their throat clamped shut. Picture is the bottom of the throat looking up towards the ears
I don't think this was a weasel or a fox. The teeth are too big. That fang mark is as big as my fingernail. I don't think it was a coyote because none of the sheep were eaten, and none were carried away. Coyotes might kill a bunch of sheep, but they'll usually carry it away, especially if they're feeding kits.
So what do I think it was? A domestic dog. Which bums me out. I've had three incidents this week with dogs from the dog park chasing and pulling feathers out of turkeys. I think that it's likely that someone thought it was cute to watch their dog "herd" the sheep and it went wrong quick, or maybe someone didn't see their dog go do this.
This is the sort of thing that makes shooting dogs a reasonable option. A few seconds and the lambs are dead.