If they are on any type of irritating bedding such as pine, or that pelleted stuff, anything that is dusty, it can make them very itchy. Hairless rats have higher care requirements than normal rats since they don't have the protective hair coat. Scratches show up easily and can become infected. Their nails need clipped if they get too long, as they can scratch themselves. They tend to get eye infections/ulcers easily. DO NOT USE CAREFRESH or similar bedding with them. It is too dusty and will ball up in the corners of their eyes and cause ulcers, which can blind them(not to mention, it's incredibly painful).

Also, please don't breed hairless females. They generally do not lactate well, if at all, and have a high rate of not having viable litters.