Rat tails are very, very, exceedingly, very, very-very (Did I mention
***VERY***) commonly just skin disease like acne or a fungal infection.
Some ferrets go bald there with age, too.  We simply do NOT think adrenal
unless the fur loss is elsewhere, vulva is up, there is thin skin, etc.
In our house when there's rat tail we treat for skin disease.
 
If you are bowing a plastic barrier be sure it's of a type which can be
safely bowed so that it won't fly apart, with jagged edges and sharp
pieces everywhere one day, and do cover sharp edges with duct tape.
 
Steve's dad is out of the hospital after triple by-pass, now it's a long
haul to change habits, and there are other ill family members (i.e. Don't
expect me to have much time)...
[Posted in FML issue 2834]