Barkingdog, I think they'd just cuddle up and go to sleep at this age. But the mess, yeah, not a good idea.
Haven't had a sheep killed by a snake yet, but we did lose a beautiful Jersey heifer, Hazel, also a foal, the latter on another property. For all I know sheep may be more aware of the danger they pose and be more careful to avoid stepping on them. The reaction when one of our cats goes through the paddock is unreal, you'd swear they think it's a lion hunting their lambs.(Hello, cat fight outside.)