Heat seizures.

[Miss Lydia]

There is also misters that can be set up I've never had to use them here but I have seen where people use them for the ducks and chickens. Maybe try putting another pool out too so Kevin can possibly use one or the other.

found this online
Misters are another way chicken keepers cool their flocks. The dry Arizona weather lends itself well to evaporative cooling. A simple, standalone mister that attaches to a garden hose can be purchased for around $12. Set up the mister in a shady area near a water supply. If you choose to set it up inside the coop or run, use caution that it doesn’t soak feed bins or overly saturate the coop floor. A slightly damp floor is cool and refreshing, a sopping wet swamp breeds disease and attracts pests.

A review https://www.backyardchickens.com/threads/water-mister-for-chickens.403559/

 

[RubelliteRose]

Do you have shady areas where Kevin can get out of the sun? We set up a few beach/patio umbrellas for our flock in the summer. If you put one by your pool and float some ice blocks in it, it may stay cool enough that you won't have to change out the water in the afternoon.

Maybe try putting another pool out too so Kevin can possibly use one or the other.

This was my other thought too

If you are in an area with very high humidity, I wouldn't bother with misters. We tried them our first summer with chickens and it just made everything feel even more damp and gross. Both the chickens and the humans hated being near the misters