Everything Despawning

I just noticed that on my world that I have had for a few months all my animals have despawned. I was building near my animal farms when I noticed all my animals were gone. I thought they had escaped but there was no way they escaped. When I went back to my base, my dogs, horses (with saddles and armor), parrots and villagers were gone. I had trapped a pink sheep in a boat in a well, and both the boat and the sheep was gone. This makes me think all entity’s were wiped? I don’t know. I made a new cow farm to replace my old cows yesterday and they have all despawned. They weren’t in a big area.