My first batch of silk worms has vanished. Somewhere between eating two leaves and becoming a cocoon. The reasons I think this may be a bug:
nobody had access to them but me.
They did not starve because there were leaves left in their chest. (after they vanished)
I am pretty sure they did not turn to moths and die because there were ten in one container, so there would be a high probability that they would have left eggs. Also, I don't think enough time had passed for this.
I will watch to see what happens to the next batch.
