I am guessing now that the potential for contamination may run somewhere around one in a million. Taking that into consideration, it is still possible. Ignoring the difference between improbable and impossible is not an option, especially when erring to the side of caution only poses the risk of losing five minutes of your time. If you have a batch that has been fermenting for six months and the chickens stop eating it, I think it is reasonable to suggest taking five minutes to start another bucket and see if they react differently to the new batch instead of immediately removing all other food options. I'm not suggesting a hysterical freak-out, just a bit of caution that could be exercised in less time than it takes to read a couple posts on BYC.
I do trust your wisdom on the subject. I'm really not all that paranoid, probably more obsessive compulsive, if I had to make diagnosis.
On that note, I will be taking your advice and abandoning my obsessive three jar mess and going with the good ol' bucket. I'm fairly slow sometimes, but eventually I catch up, ...finally realized that they will be getting plenty of well-fermented feed and not a bunch of the fresh stuff from the day before
if the container has more than a couple days worth of feed in it. (DUH! I told you I'm slow. Thank you for your patience.)