Yes, we have a swimming pool for the chicks. That's me in the costume, encouraging little Nacho to swim faster.
They make little contact calls while in the pool (the same calls they make when they are being fed). It kinda sounds like a little "whiiirrr". It let's me know they are happy, and feel safe.
We reward them for all their efforts during the exercise, but the ultimate reward is the proper development of the chick's legs.