Why isn't my Minecraft wither skeleton farm spawning any wither skeletons?

Question

I made a wither skeleton farm made by MCblockinvasion in a Minecraft SMP server.

Here are the spawning pads:

I slabbed the nether in a 128 radius around the farm.

There are no mobs spawning at the farm, and I am certain that I am far away enough for them to spawn. In this next picture, you can see that there is 15 mobs loaded, but no mobs are spawning in my farm anyways to reach the mob cap.

Keep in mind that even when nobody is online the server, the mobs still aren't spawning. Any help is appreciated.

Answer 1

Replace the stone brick slabs with full blocks and make sure that your landing pads definately have 3-4 blocks of open space above them.

Also wither skeletons have specific light conditions requiring them to spawn the wiki page is linked below.

• Wither skeletons will only spawn near Nether fortress in light levels of 7 or less.
• Wither Skeletons can spawn in a 2.5 block tall space

https://minecraft.wiki/w/Wither_Skeleton#Spawning

Wither skeletons are a rare spawn so don't expect extremely high rates but the above should sort out your spawning issues.

Answer 2

I'm not the techiest gamer, but I think there are 3 possible places where you could have made a mistake.

1. Your slabs seem to be correct in the picture you posted, but double-check that they are on the BOTTOM side, not the top. If not, then mobs will spawn on them and disperse, thus you will have less mobs spawns in your farm.

2. The textures in the last picture appear to be glass on the ground? Mobs will not spawn on glass.

3. Check that you are not in playing in peaceful.

Answer 3

I think the problem is your rendering distance maybe if you set the value in 10+ you should start to see mobs spawning

Answer 4

Things that could have gone wrong:

• They only spawn at low light levels.
• They must spawn on a full block. (No slabs, stairs, etc.)
• They only spawn on solid blocks. (They don't spawn on glass!)
• The area above them must be at least 3 blocks tall. (Thats right, 3, not 2.5)

They do not need to be on a nether fortress to spawn. The spawn rate is already pretty low normally.

Also, make sure that your game is currently set to something other than peaceful. If you went to another peaceful world then came back, your setting may stay on peaceful. Although not very likely, there may also be internal game settings that were altered preventing mob spawning. For example, make sure the gamerule doMobSpawning is set to true:

/gamerule doMobSpawning true

Answer 5

I can see from your screenshot you are at Y:20. My guess is the fortress bounding box does not go this low, but you have to download a bounding box mod and verify.