Thanks for this Chelle.
I tried many of those methods for Thumper when he couldn't stretch out & was overheating alarmingly. His ears went red too!
Trouble with Thumper was that his fur was so thick he couldn't feel the cool, so he rested his plums on it. :shock: Thinks *he's going to be the 1st bunny in history to neuter himself with cryosurgery*. :shock:
Eventually Marie gave him a special fur cut.
And feet too.
Although neither species can sweat, they can also lose heat by evaporating water from the lungs & upper airways hence the increased respiratory rate.
Not big enough for a rabbit, but may be OK for a chincilla is a huge unglazed ceranic plant pot with tunnel in. Soak the plant pot in water overnight. As the water evaporates from the outside it's delightfully cool on the inside.
(Old fashioned way to stop milk going off, or butter melting before we had fridges!)