Hello paynemom,
I would say no it isnt. I live in SouthCarolina and at nights it's 35-40 and days 50-65 and when I hatch day old chicks in the winter I keep them inside for one week and then move them to outside with a light for heat during cold days and always at nights.
Summer hatches I keep them inside for one week, then move them outside with only a little or no light at all at night. It's 80 during the nights here in the summer so they are fine.
Keep them in the brooder for a while and then move them outside but with a light, I dont reccomend you putting them on the ground at such a young age,
See what other members have to say on this part of the topic also, lots of great members here!
They should be fine together and the only time you should ever be awared is if when they get older about the roo's , they seem to want to fight sometimes.
They should be fine in the heat of the summer, make sure they have plenty of water!
Predetors, I dont know what kind there are in Arizona but thats what you have to look out for when you move them outside, this is another reason not to put them on the ground in the start. Make sure the pen or cage you keep them in is "proofed" no holes where snakes, rats etc. can "slip" through.
Chickens are a true joy, and I hope the best for you.
Keep us updated
~LowCountry Poultry