After looking closer at the pics now, I would say she is chewing herself.  Some pigs do that.  Soem say it is genetic and some say it is learned.  Since her mom doesn't chew it wasn't learned, but her dad chewed, so it may be genetic.  Her brother isn't chewing himself so far.  Sorry you had so many problems with her.  Hopefully the next one will be better.

JCD's Caviary 384 days ago

Or the coat could have become burned from the urine & broken

Cherished Cavies 384 days ago

IME with Texels at least, is IS inherited but not all inherit it, they chew their sides mostly, and can end up with a little unchewed long "rat tail" of coat in the back compared to the shortened sides. So I lean toward Dorothy's burnt-off theory for the rear. That IS a dirty bum. Besides what I said in the Group discussion, frequent baths would also help.

Shelley 380 days ago

Looking at the photos where she is being held in the hand the butt was not stained, broken or chewed so in my opinion the fault is not that of the baby sow but the lack of adequate space and/or failure to keep the cage clean.  If adding more frequent baths do only the stained hair nad not the entire sow so the remainder of the coat and skin does not become dired out.

Cherished Cavies 380 days ago