We're having unusual weather in the UK this year, with the rainy Summers being replaced by hot, sunny weather.
Chickens can't sweat like us; they have to find other ways to keep cool. They pant, drink more water and seek shade. In really warm weather you may want to make them more comfortable with the following ideas.
1. Provide shade. If you have a moveable run, place it under a tree,or shady place. Just keeping your hens out of direct sun will help considerably. If your run is stationary, wet a white sheet and sling it over the run. Make sure the sheet is white as this will reflect the sunlight away from the run, and if it is wet the water will begin to evaporate, taking the heat away with it. The sheet may need dampening again throughout the day. If your chickens are free-range, they should be able to find shade under a bush or tree themselves but it's good to try one of the above ideas anyway, so you can be quite sure they have a cooler place to go.
2. Water Trough. You could try lining a shallow tray with pebbles and then filling it with water. The hens will stand in this to keep cool. Another option is pouring water onto the ground to form a muddy puddle. They can sit and scratch in it.
3. High water content food. My hens love watermelon in hot weather, and it really does help to keep them cool. Other high water content foods can be given and are enjoyed, particularly if they have just come out the fridge!
4. Ice. You can place a few ice cubes in the water hopper to keep the water cool in the day, or you can freeze a plastic bottle filled with water and place it in the run. The hens can sit next to it to keep cool.
5. Hose Pipe. Hosing down the run a little will keep the ground cooler and if you use a spray attachment then you can spray your hens too! This should only be done if they want it and if the spray is fine. Don't actually hose down the chickens, or soak them, this is not good for them! However, a mist spray will help keep the air cool and moist.
I hope these ideas help and I hope you and your chickens enjoy the rest of the Summer!