Don't give me flak for this, but the nest box lid doesn't have a latch at all. What's the likelihood that a racoon can figure out how to hold the lid while grabbing a chick? Maybe I'm just being naive... But I did think about that. It didn't come with a latch and I just never thought about predators as much. Also, that lid is heavy... I just never thought a coon would be able to lift it.
As for weasels, the thing with my situation is that one of eight went missing. Then this morning two more got taken away. As we were digging thru the debris in the backyard, we found the mottled cochin's pile of feathers. Just a neat little pile of like 8 feathers. Same thing with the white cochin. No body, no extreme amount of feathers in coop building, no blood.