I've had my two male degus for just under a year (around 10 months). They have their odd scraps but I haven't witnessed any major fights. Recently though I have noticed that Gonzo has some fur loss on the back of his neck (behind his left ear and just above his shoulder blade).
The skin isn't red or broken and he doesn't seem to be in pain, nor has he been scratching any more (so don't think it's fleas/mites - plus I give them dust bath regularly and change the dust at least once a week). His brother Magpie doesn't have any signs of fur loss although the area concerned (on Gonzo) does appear to be a favourite grooming Magpie's.
Is this just a possible case of over grooming on Magpie's part or could there be something more serious going on?
Your help in this matter would be gratefully appreciated.