Yes! My girls love any kind of liquid dairy: yogurt, milk, whey. We make our own yogurt and cheese, and when we have a little leftover milk in a grandkid's glass, we save it for the hen's afternoon treat. They love it any way you want to present it to them. Yesterday, I only had a little whey left from cheese-making, so, to extend it, I mixed in a little of their organic feed (from Countryside), and they went for it same as always.
They get really excited when they see me walking up with anything that looks like milk or yogurt. It's fun to be so welcomed by chickens!
-harvey