In my Minecraft survival world I had around 15 mooshrooms cows which I had attatched nametags to. A couple days later I realised that all but 4 had despawned on my property.

I do also have a village attached to my property but I thought because I have the mooshrooms nametagged the amount of mobs in proximity to me shouldn’t despawn them?

Also I’m 99% sure they haven’t died because there is nowhere for them to take damage really and this hasn’t happened for the last 6 months-ish of playtime.

This also happened a second time once I bred them all again and name tagged them, only for all but 5 to despawn.