Tamed Mobs/Animals Disappearing

Several of my tamed mobs/animals disappeared today. I had a fully enclosed pen with sheep and a llama, a fully enclosed pen with cows and a llama, a horse equipped with a saddle that was attached to a fence post with a lead, and a wolf/dog sitting in my house. I went down in into my mine (y level -56) that is next to my house for about 30 minutes, when I came back up to my fenced in property and house, all of the animals/mobs listed above disappeared. I tried exiting and reentering the game and I tried moving at least 64 blocks away from my property and back but the mobs/animals were still gone.