I did water about as warm as their brooder was supposed to be. So if the brooder was 90, the water was close to that. Brooder was 85, water was close to that.
I brought them in for the first couple of weeks to swim in the tub, but let them run around the bathroom for a while first. Swim last, towel dry and back out to their kennel in the heat and under their light.
They are a week or so old. We ended up using only warm water for their bath. They showed no signs of being cold. It was a fun time! Now I know they would like it DEEPER also. Oops, I under estimated their abilities! I think swim time will be a new ritual for after TT (terrible two) goes to bed.
At about 2 weeks I started putting mine in the bath tub. Warm not hot water and not so deep as they can stand up in. I started by letting them swim for about 5 minutes and increased time with each swim. After I towel dried them and put them back in brooder. As they grew so did the depth of the water. After about a week I put a small tub that they could get into and out easily in the brooder so they could clean as needed but still let them have bath time once a day. Made a royal mess in the brooder but they loved it.