If she was allready smelling pretty bad , my thoughts would have to be a late term abortion. The lamb is dead and decaying, the ewe will not dialate properly, and she will allready be toxic from the toxins released from the dead fetus. Nothing you can do with some of these,depending on the cause of the abortion.
In the case of an emergency c-section. As soon as the ewes heart stops pumping blood, the fetus begins to "suffocate" no blood , no oxygen. . I would have everything ready, shoot her, and cut her open. Depending on how close the ewes was to delivery, will decide the fate of the lambs. But 2 or 3 minutes at best.How long can you hold your breath? About that long They have to be at least 143 or more days gestation, or the odds are slim to none of haveing viable lambs. I have had very few that I saved. I have not had one that I had to do in years. Mostly a problem of old ewes, vitaimn, mineral problems, thin ewes, or ewes that have a litter and are losing ground fast.The lambs are weak and problematic as well.
Based on the descrition of the ewe, the lambs were dead for at least 24 hrs.
Starving sheepherder on the windblown tundra of Northwest Iowa