Lunnaris - my bedroom can get pretty chilly in the wintertime so I started using a small ceramic heater. Well, not only did my skin and nose dry out but also the gliders fur. They all had that cracked look about them. From that time on, I added vitamin E to their mixture and have not had any "cracked" fur since.
My vet recommended adding a couple of drops of vitamin E to their diet.
Since vitamin E tastes really, REALLY nasty - I suggest adding a drop to their nightly HPW mixture. Then when you make your next batch, add about 4 - 5 drops to the mixture.
I purchased the NOW brand of liquid vitamin E at our local health food store. One small bottle will last a very long time.