We lost a third of the hens in one of our henhouses once. All the birds in the top tier of cages died from heat stress when the fans stopped.
The fan control box failed, with several burnt components. This was sufficient for insurer to pay out on the fire part of the policy.
After that over temperature alarms were fitted.
Must have been a nightmare, we have loads of electrical checks, a back up generator and alarms sent to four people now.
On top of that last time the forecast was for over 28C we thinned out with a small crop of poussins.
Might have to train the staff with a burning out capacitor smell.