Well Roland....as I stated in the thread you quoted me from.....i get it near very year. I have changed lots of things and many stock birds have come and gone and it still appears. I have a family of Kirkpatricka that will be as old as you that get it also....hardy *expletive removed* that I get regular in stinkers. So I am afraid.....yet again .....that we will disagree on inbreeding or genetics from parents being the cause of ybs. As for stigma ......none attached for me. If yer looking after the birds well then you should be on it the first day it appears and with a few natural products or even a touch of Roni you will have it sorted in less than a week. No adverse affects seen later.