One of our guardian alpacas going back out with a mob of ewes and marked lambs.
Not all alpacas are created equal in the caretaker stakes. Some are much better protectors than others, some like to shepard their sheep away from potential threats and some like to face them head on. Some probably do the alpaca equivalent of sticking your fingers in your ears and humming really loudly too!
The alpacas do object to dogs though, including (but not limited to) our own dogs, wild dog/dingo and such random passing pooches as we might see, so while they aren’t a silver bullet against predation, they are certainly a good help with the sheep while they are close to lambing.