Found a nice village,  fenced it off,  fully lit up all dark areas,  rooves,  etc.  Buuly a giant house with 40 beds,  bred the villagers to fill about 25 of them,  built enclosures for sheep and chickens,  and went mining.  Came back,  and all the villagers and livestock was gone.  Frustrated,  turned to Google,  and since I was on peaceful,  no mobs couldve killed them,  found no help.  10 in-game days later,  they are still gone.  An entire giant village,  empty.  The villagers all had jobs assigned,  were fully protected,  etc.