Today's high was 44.4C (112F).
The chicks have done remarkably well! I've just been cleaning up their brooder and they're bouncing around and cheeping to their heart's content.
The fan was on all day and I renewed their water and added ice as often as I could. I also decided to allow Blossom to have access to the chicks' room to allow the air conditioning to flow through to them a little, which I think probably took the edge off. Blossom spent most of the day asleep in the spare bedroom, so it was all good, although I was excessively vigilant.