Hairless/double rex rats often show up in rescues, as with any other, and some breeders do work in hairless also. TRUE hairless is rare, more often what you are seeing is double rex with very very little coat, often just a little fuzz around the face.
Hairless rats are pretty much the same as our furred guys. They are warm to the touch, and are prone to the occasional minor eye/skin issue.... ingrown hairs can get infected and look icky but often don't cause any more trouble than that. They do mark up a lot faster than our furred rats and often people think they are being beat up but they aren't, cagemate claws just slice them up faster since they have no hair to protect them.
Higher metabolism to help keep up their body heat might cause them to eat more. And having cagemates obviously helps with the body heat situation.
