no control, we kept one of the possible 2 troughs full-ish throughout, and sprayed as they began pipping, drained most of the trough to prevent them falling in & drowning.
Wondered if the spraying might have baked the shells, or filled the air sack?
We had 2 warrenXsilkies of our own (one hatched then died) and 6 cuckoo Marans via the internet (half fully formed but died in shell)
Ive got a hygrometer (?!) humidity measurer ordered....