Down here today's forecast has jumped from 42 to 45, so it'll probably reach 46 or 47. The BoM hasn't quite nailed the forecasts for heatwaves yet. It's usually hotter than they predict.
So I'm rethinking the chickens options. I might put the sprinkler on for them in the yard where there's shade til lunchtime. Or I might go get a few bags of ice to stack in the henhouse.
I have never had these problems. It is fascinating to me. You are very clever to help them as you have.