Choc Wise it is an old/new problem. The initial problem was fixed and there was much rejoicing. When we had the original problem the fix was to dig one block down, fence the inside of that block and pen the animals that way which kept them, mostly in place. The developers addressed the problem and you could start using fences properly.
It does still seem to work but in the case of chickens they now get stuck in the small space between the fence and the block and you cannot interact with them. I haven't been on recently since I did this but I think it solved suffocation and escapees.
Unfortunately too much effort I believe has been placed by the developers in adding new features that many of us probably will not use such as much of the recent redstone items. Most of which are completely useless in survival. For me anyway since I have not built anything using creative type tools since before survival was released.
The performance of the PC in question, I would say, has nothing to do with the issue. I still have the issue but run into the hundreds of FPS. It is great that Minecraft is popular, and that time and effort is still being invested in it but recently I find the developers are going off into their own little world (polite way of saying) and the result is you have devs blaming peoples computers for the massive FPS drop of terrible coding. Rather than tweak the game to give people what they want, essentially more block types to build with they are changing direction in a way that is A) breaking the game or B) driving original players away.
Crash report generated during bug
and in snapshot 18C, animals push against fence boundaries before popping through them. If you use the old make a pit and place fences in the lower level the mobs get trapped between the fence and the block preventing player from clicking on them or killing them without destroying the fence.
Mods-please note it is very difficult to search for duplicate issues when people use different words to phrase reports. Nearly every report cites a different reason for the cause. And yes, I did search but I do not have the time to go through every report with the word zombie in it.
We are taking the time to freely report bugs for a game we have paid for, at least show a little bit of thanks rather than whining about duplicate issues. You are getting free, crowd sourced testing and reporting. To be honest I don't think I will waste anymore of my time helping Mojang make more money.
Zombies caught in the act on the 17A snapshot.
Zombies fall from a fair height. this is the fourth zombie daylight siege in this daytime cycle. Approximately 5-20, perhaps more, zombies per siege.
Also note zombie landed on blacksmith half block and does not burn.
5 villagers were killed during this update. 😞
Edited snapshot, it was 16b and not 17a, launcher was showing new version even though it couldn't use it.
Not the best example as I was fighting the gold plated freak at the time but these three zombies dropped from the sky. A fourth Zombie died on impact (chute didn't open).
The zombies often die not long after dropping as they take damage from falling and burning. Some who land on buildings, hills do manage to turn villagers.
Just to confirm this is happening across two different clients/worlds for us. It started with 1.5, shock horror, golems stuck in the attack cycle will not do anything else even when attacked. Thus dying at the hands of skeletons.
"Complaining that they're adding new features instead of placing their entire task-force on bug-fixing just because you don't use the new stuff is silly."
I have nothing against new features. But adding new features in one hand and breaking core stability of the game on the other hand is not good. Secondly it is unlikely a huge problem. It is very likely they know exactly what caused it as it has been fixed before. The fact that, after all this time, they have not assigned "anybody" speaks volumes. Yet they continue messing the game in various ways. I did not complain they were adding new features nor did I ask for everyone in the office to work on it. You were not being harsh you were twisting my words to suit your own interpretation. They can continue to add features I see as pointless as long as the game itself isn't affected. I can choose not to use those features.
The Devs put a lot of stock in the "Redstone Update" I am glad you find the update useful and use the content. I am sure many others do as well. Recently there has been many reports of them "squashing" bugs. Most of those bugs were caused by them not sufficiently quality testing the patch and pushing it anyway. This is a core problem with developers these days, releasing unfinished garbage without allocating time to test and troubleshoot. The Redstone update reduced my framerates by well over 60% to the point where I had to use a player created mod to increase frame rate and had the bonus of actually making the game look better at the same time.
Minecraft is one of the those games that never really needed massive new updates or content. I would place a fair bet that a significant number of players just want simple things like different textured blocks or coloured glass. Judging by the huge number of player created content.
Lastly a number of people seem to be focused on the chunk loading and unloading, or saving and exiting. I have stood and watched a chicken run at a fence post repeatedly pushing at it until it goes through it. The chicken, a full grown one, did not appear like that. It started in the middle of the pen and moved against it. If you notice the behaviour of all the animals they repeatedly push against fences. The problem does relate to smaller animals only as I've never seen it occur with a full grown cow or sheep. It is also prone to occur if your pen is overcrowded.