I don't know what it is about these things. Maybe their spawn field is just too large, or something, but they're a huge pain to track down and kill for any purpose. Particularly hard is trying to gather those breeder eyes... You're looking at a good hour of hunting for a measly 5 or 6 components - not from lack of drop rates, but from lack of mobs. Might I suggest that the field get a bit of a jolt in spawn rates?