In my chicken egg farm, I had 36 chickens in the same space, I used two block high wall with no gaps, hopper downwards, pointing toward a barrel. I went into the nether and did a little mining came back, then so I found no eggs after a while. I checked if the chickens are okay, then all were vanished. I searched for many options.
I even saw the game rules that luring, feeding makes them persistent. Yes, I hatched them using eggs but I lured them and put them all inside. I often used pumpkin seeds to breed them.
They could die of suffocation, they could die of entity-cramming, but all these steps leave the loot which I didn't get.
It really feels so sad when I am progressing in a hardcore world. I don't really feel it has to do something with my device.
The version I use is not in the list, it is 1.26.51.1 release. I selected 26.50 getting no other option.
Actually, the seed itself has been buggy from the day I started playing. It generated a zombie villager in the fully lit, small tunnel I made. It also spawned witch very closely, the moment I broke a block, which was just a block with no empty space nearby, dropped zombie, baby zombie across turns. (1 time baby another time adult.) Another co-existing bug.