I have a six of my week old ornamental in a box in a spare room, heat lamp at night. my sixteen 6 week olds free range, and i put them up at night, so far no problem they hang out in the shade and seem fine, i bought my six ornamental at pratts so I didn't worry about delivery, the others i got at a different feed store. I am in AZ as well, do you coop them? mine are messing up my porch something terrible, we have to pressure wash every other day, but for now the porch is not used and it seems to work for my pullets, I am going to spray them down and leave some standing water for them, just read frozen water bottles work well too, as for the chicks I will move t hem to outside in a temporary coop 4 x4 separate from the others in about 3 weeks. what works for me is just a tuppawear bin, fill the bottom with dirt and put water and food in, a red heat lamp for night when the AC is on, leave in a bathroom or spare room disregard smell and charm company with cute fuzziness they forget the chicken smell, but you can shovel out dirt and add new dirt, it really works, absorbent, cheap, available! we don't use pesticides on our dirt, and added bonus if they find bugs in it, they love to scratch and use the old dirt as fertilizer or compost plus it is good for keeping them from getting splayed legs and keeps them dry and they can take dust baths, all around found this to be the safest, cleanest way to go about it.
other things i just read to do is frozen peas or berries to eat
ice in water.
good luck braving it! we are on the west side so so so hot!!!!!