My chickens suffer from the summer heat here...we get into triple digits most of the summer...100-105 for the most part last summer, but it was dry (drought) and the nights cooled down.
I think it is so great you are getting in touch with other desert dwellers, because they will have know-how to beat the heat. In the time I have been on BYC, I think I have seen a couple members in that general area. What is the marine base on the other side of Joshua Tree? - and maybe even some to the south. -- IF you don't get instant replys --so many messages flood on to BYC that they get buried fast.
There is a where-am-I-where-are-you section..... you may be able to find some folks there. Mainly -- keep trying to locate neighbors...and don't get discouraged. :O)
Not last year, but the summer before, it got up to 115 here. I did just what you said...I put my chickens in pet carriers and took them into air conditioning. I have a chart posted about chickens and heat (heat stroke) I will come back and put in a link. Three is a good number...and it was exactly three that I had at that time.