Disappearing Animals and Text, Anvils not renaming

I've been having issues with pigs and cows vanishing from their pen - I keep breeding them and all but a few will have vanished by my next login.  Today, one of my llamas vanished from his pen and my horse - who has been tamed and name tagged - disappeared from his stable. 

Signs are also an issue.  I'll write a new sign and the text will be there, but when I log back into the game, the sign will be in place but the text will vanish.

Anvils will not rename items.