Hello, this is Dr. Linda. I hope I can help with your question today.
Heat can definitely take a toll on chickens ( as well as the rest of us ), so I am very glad you had the sense to get them to a cooler area. Most people can not bring their birds indoors, so I have them place fans blowing over frozen liter pop bottles to try & cool down the coops.
The GI tract is very sensitive to elevated temperatures, & the lining can slough fairly easily. Fortunately, this also heals very quickly. Any stress, but especially heat, can exacerbate any problems in the gut especially parasites. Coccidia is one that immediately comes to mind. It would not hurt to deworm your birds with something like amprolium, but you can also gather some stool samples to take to your veterinarian for analysis.
It is not unusual for laying to slow down in the heat. My flock's egg production is cut 50% during heat waves. It picks up within a week or so after it cools down a bit. Make sure the scratch is only 10-20 % of the total diet, as it will make your hens too fat & this will affect egg production as well. You can bump it up a little if it gets cold enough in the winter. As long as she is still eating & her color is good, then she may have just gotten a little heat stressed & will be fine.
I hope this makes sense & you find the information helpful. Please let me know if you have any further questions or concerns.