Caterpillars falling from mesh roof of cage

This is not a common issue. If you have caterpillars falling from the mesh roof of the cage, it's most likely for these reasons:

1. The caterpillars are sick and not spinning enough silk to from their chrysalis. Heavy OE infection is a possibility:

Monarch OE and Prevention

2. The cages are in an area where they are exposed to extreme weather conditions like wind and/or heavy rain.