Margaret and Rufus,
There are several things that could be causing the scales.
1)Poor nutrition--Even if he is recieving a proper diet now there are
intestional problems that can decrease the amount of food he is able to
absorb from his GI tract.  Usually you would see other symptoms of GI
problems (loose stools, poor appetite, weight loss).  The other possibility
is if the other ferret dominates the food.
2)Trauma--if he is not used to playing rough or if the area where he is kept
has flooring that is more coarse then he is used to.
3)Ringworm-- this is a fungal infection that can look like this.  your vet
can culture the scales to diagnose this.  This is treatable with topical and
sometimes oral medication.  This can be transmisable to people and other
ferrets.
4)bacterial skin infection can also cause this and is usually easily
treatable with antibiotics.
[Posted in FML issue 1121]