How hot can a baby chick handle?

My new flocks of 35 chicks just turn 2 weeks old. In the past week I had brought them outdoors for the day since temperature was at high 80s. But the next few days it will get up to over 100 F. I won't be home around the hottest part of the day. Will the chickens be OK or I'd better keep them inside? Any chicken owners on Texas here? How does a mama hen keep the chicks cool in hot days?

Last year I had chicks outdoors during a similar heat wave. They didn't even need any heat at night after a few weeks. They were in the shade and had plenty of water, and didn't seem to suffer.

I second what Juniper said. Shade and cool water. If the chicks were left out in the sun, they probably would have problems or possibly die. If they have shade and cool water to drink, they should be fine. Some people refill the waterer throughout the day. Others stuff it with ice cubes before they leave. Different methods for keeping the water cool.

Shade and cool water. A mister if you can get it, or a damp area on the ground. I have some low, flat water containers and sometimes the chickens will stand in them. They lay down on the damp ground, in the shade, and pant.
Misters can help adult birds.

Otherwise? Float ice cubes in the water - but don't give them only ice.

I have a broody hen who decided to nest outside, no shelter, under a bush. With our local lack of rain, I'm doing my best to keep her under shade, and she just does her best to shelter the eggs while hovering over them since it's so hot she is a slightly lower temp than the air.
Texas can get wild!
 

Baby chicks were doing fine at 96 today while my big chickens were panting and holding wings open all the time. I refilled the waterer with cold water before I left and everything was fine. I am going to make a little mud puddle tomorrow.  It sounds like something fun for them to play with too.

My teenagers like to bed in the slightly damp spots in the shade.
The adults tend to walk around with their wings open. They look like they're posing at a gym.
I have a few hens who seem to enjoy wading in the low flat water dishes, so those get refilled every day.

One of the big problems with chickens in heat is that they don't get enough water to make up for what they lose by panting. Your egg numbers and sizes will go down during the heat as they will lay less frequently and will lay smaller eggs. This starts around 85F and will continue until the temperature drops. Anything that encourages them to drink more water or that otherwise incorporates water into their diet is a great idea for them.

Watermelon, other melons, and other water dense fruits and veggies make for great treats for summertime. I make sure the "wet" feed I offer is even wetter, so they have water added to their diet.
Offering calcium supplements (eggshell, mineral salts, whatever) is also useful since they depend on water to help with that and it's one of the first minerals that really shows deficit early. Giving them ways to keep their calcium/magnesium levels balanced outside of feed offerings can really help.

It sounds like you have a great setup and your chicks will be fine. August will be here before you know it, so learning what your chicks like to do to beat the heat is very helpful!