I’m pretty new at all this and trying to reconcile recommendations for cold treats with things I’ve read about growing pullets really needing to only eat their grower feed for fear of nutritional imbalances so my compromise was to make them “chicken ice cream” which is their regular grower food mashed up with chilled Rooster Booster electrolytes (not a ton, just enough to moisten) plus a few chopped frozen blueberries to keep things cold. Sometimes yogurt instead of the Rooster Booster. It’s mostly their regular food, though. They still go wild for it like it’s the most incredibly delicious stuff and making their regular food cold and slightly differently flavored still seems to make them feel like they’re getting a really exciting treat.
Try it with just cold water and chicken food-- in my experience, chickens go crazy for it that way too. It's even easier to make, and no worries at all about un-balancing their diet.