My Buffs do that when it's hot outside, they're a little older than yours. My husband thinks it looks hilarious and I just keep an eye on them in case they start showing signs of heat trouble. My guess is that plastic(?) tub thing is cool to the touch and she's just enjoying it for a minute. Watch for wobbling, head hanging, lethargy in general. I did have to bring one girl into the garage (it's cooler in there during the day) for two days after she got a little too much heat and started acting funny. Caught it as soon as she started presenting symptoms and she has recovered nicely.