Flyer tail fur thinning

[fultonflyer]

Greetings to all,
I have 10 yr old flyer “Dink”
He seems to have periodic thinning fur of his tail only.
I don’t see him bugging at it during these episodes which is like perhaps 3 times a year.
Hos sort consists of Henry’s blocks 1/2 block twice daily; sweetie potato slice;broccoli;romaine; dandelion; mushroom; pumpkin seeds; nuts;
Does anyone else have similar experience with their flyer’s tail?
[ATTACH]320845

[Mel1959]

I’m not sure what would cause this unless it’s seasonal or he’s self barbering. My flyer did some self barbering, but it was right down the middle of the underside of the tail. That eventually stopped and he’s never done it again.