Today I downloaded a custom world. It's terrific, just what I wanted for a particular family, but there is one thing I don't like. There don't seem to be any spawners. 36 hours into residence, the only ones I've found are for fish. Despite looking extensively throughout the world, I have seen not a single seed, rock or minor pet. Unfortunately, I'm not able to inquire of the world's creator if they were included. How do I go about determining whether they've been placed?