I am not sure why we are fairing the heat well. It has been over 100 almost every day for the last 2 months. It has been record breaking. This week we will be 105-107, with high heat indexes. We are still getting 7-8 eggs out of 9 layers. I spray the coop down if it gets super hot, we let the girls out to run around most days.
The only thing I can think of is we have had some breezes and we have a pool, (maybe the pool cools the air around) We have had friends loose birds to the heat and seems everyone else is too. (One of our girls went broody and I looked around for fertile eggs, since we dont have a rooster, and noone had any because their girls quit laying).
Our rabbits have all done well too and they do not handle heat well at all. We have 5 in a colony and they have survived. (They are not getting pg, but that is okay by me until this heat stops, if it ever stops.)
Edited to add: Sorry for your loss.