Can you hang some cotton sheets or similar over the pen then hose or bucket water over sheets to make them wet, then get a fan in there, are they in a coop, have you got somewhere safe for them to get out of there and under a shrub or tree?
We get those temps here in Australia but mine freerange as we dont have the predators here. Mine always get under a shrub and have dirtbaths to cool off, I also spray them with fine mist from hose, they dont like it but it makes them look cool! not sure if it helps.
Put some ice in drinking water too,.
Another hint is to put yourself in their shoes and pretend you are in there and see what you would do to make it more comfy for you! it seems to help add a new perspective.
Make heaps of shade!!!
I really hope you get through this,
Hugs
Helen