Do the windows have curtains? Is the room air conditioned? If the windows have curtains giving them cool treats should help. I note you're in Texas? Yeah, you guys can't really avoid the heat down there. :lol:
Um... dog food can actually be a portion of a balanced diet, but it shouldn't be the whole of the diet. Perhaps look into something like the Harlan Teklad Lab blocks and Suebee's Mix.
As for a bath, many rats do not like water and they do clean themselves. So often there isn't a need for a bath unless they have gotten themselves very dirty, aren't cleaning themselves, or are injured (or some other pressing matter). Be prepared to get the daylights scratched out of you, especially the first time.
Some people have good luck filling the bath (sink, etc) with water, dipping the rat in (not the head or ears!) and then soaping them up (puppy shampoo works) and then dip until rinsed. I wash my boys under a running tap. They weren't buying this 'dip' idea.
You will know your rat is hot when he lies flat like a pancake or lies on his back and sides with his paws in the air (they dispense heat thru their paws).
If he's in a wire cage, has a fan (make sure he can get out of the fan's blowing path), he should be fine. If he starts showing signs of heat, you can always do things like freeze a small plastic waterbottle, then cover it with a sock, and put it in the cage. He will cuddle up to the coolness.
Dog kibble can be a part of their food, but since it is seriously lacking in Vitamin K it cannot be their proper diet.
The best thing is to try to find good quality lab blocks as they were created as a complete diet for a rat's entire life. You can then supplement with veggies and some fruit and protein.
Stay away from all seed rodent mixes, stay away from Sunseed and Kaytee as well.
about bathing. I only bath rats that are older and need help, or if someone has gotten into something, or possibly a very greasy hormonal buckrat. A rat fully bathes itself many many times in a day and are probably cleaner than us. They do not need baths by you at all.
It's getting warm here now and all of my rats are showing the signs of being overheated that lilspaz has mentioned.
My Beatrix loves to have ice cubes put in her water dish, she'll pick them up in her paws and shave bits off with her teeth. I put ice cubes in Doris' water bottle as well, just to help keep her cool. I find their body odour gets to be more unpleasant in the heat as well, so the two girls I can handle, I give cool baths. They claw and get upset but it really cools them off when they get out of the bath and they seem much more comfortable afterwards.
The most important thing for you to do when it is very hot is to make sure their water is changed often and is always cool. Bacteria thrives in heat, and if you let their water sit for too long, it will become a cesspool, and they are much more likely to become ill.
I also buy Breyer's sugar-free real fruit popsicles (ice lolly's, whatever you call them) for myself, and the rats love a bit of that in the heat.