The case of the dead sheep

Question

I have four compact wool farms, each of which features a sheep of a different color standing in a 1x1x2 area, completely enclosed with glass blocks, except for the bottom block which is obviously a grass/dirt block. The wool is collected by a hopper in a minecart underneath the grass block and moved into a chest. One day, I come back to the farm to find one of the sheep missing. I jumped around the glass blocks to make sure I hadn't forgotten to cover any sides which could potentially let the sheep escape. The 1x1x2 area where the sheep used to live was completely covered from all sides. Then I opened the chest. In it I found not only wool, but also two cooked mutton. This means my cheep has died of fire. So, what could have potentially killed my sheep?

I've had the following theories

• Some mob spawned inside the 1x1x2 area where the sheep was. However, I find this unlikely because the glass block above the sheep has a torch placed on it, so the light level inside the enclosure is 12 or 13. I don't imagine any nether creatures spawning in the overworld which are the only ones that could kill something with fire.

• Lightning? But then my sheep is enclosed in glass and under a roof. Glass protects from lightning, doesn't it? If it doesn't, and my sheep was in fact killed by a lightning bolt, how could one farm sheep safely? The reason I my roof is made of glass is that the wiki says that grass cannot grow under solid or light-blocking blocks and:

  Grass can grow under all other transparent blocks, like glass, fences, torches, or pistons.

1.14.4,Java edition, Survival mode, Normal difficulty.

Answer 1

Lightning has a certain range of damage, no matter how many blocks are in between. The only way to protect your sheep against that is placing a block a lot higher up, for example 10 blocks higher should be safe. Lightning only ever strikes the top block in a column (except when summoned by a command).

There is also a bug allowing mobs to hit or shoot through corners, so in theory a skeleton with a Flame bow could have tried to shoot something else and accidentally shot exactly the corner of your sheep pen. But that is so incredibly unlikely that we can safely assume that it was lightning.

Answer 2

Just to add to this, I had a 3x18 sheep farm, one of each color, observers and dispensers wtih shears behind them, a collection rail under them, with (color matched) stained glass blocks enclosing them on the front and top. One day I noticed that about half my sheep had vanished, then a day or so later the others vanished as well. I checked my wool collection system and found 16 cooked mutton. The only thing I can think of would be lightning strikes. Strangely, the hopper minecart I had running on the track under the sheep has vanished now as well.