Wither Skeleton head?

[Toadzilla]

So I have a T5 Wither skeleton spawner set up to drop them into a hole with the floor as transposers, which leads into barrels to collect the items. So far I have 116 stacks of bones and 18 stacks of coal, but I have not gotten a skull yet. Is this normal? (Should i expect to wait a lot longer for one to drop?) Or do you have to kill the skeleton yourself in order to get the skeleton's head.

Thanks

 

[Yusunoha]

yes, that is normal. the skeleton head is considered a rare drop, and shadowdrgn changed it in his recent updates that most of the rare drops don't automatically get dropped when a mob dies like that with a soul shard spawner.
solution is to kill them yourself, or have a turtle do it.