There are several post here after doing a search on Apple Cider Vinegar/ACV:
https://www.backyardchickens.com/search-forum.php?cx=partner-pub-9473214521653913%3Abil3pz2p90m&cof=FORID%3A10&ie=ISO-8859-1&q=Apple+Cider+Vinegar&sa=Search#1228
Hope this helps!
Dawn