Go to the scene where Dr. Grant and the rest of them are looking at the pen filled with raptors. They show the cow being lowered in for feeding time, a bunch or rustling, squeals, and growls, and then it shows the broken and torn up sling being pulled from the pen - which is completely clean! If the raptors really did tear apart the cow, as shown by the condition of the sling and the noises made by the animals, there should be blood all over the sling. Yet, there is not even a drop.