Mobs Mess Up

This is also a slight suggestion when the glitch is fixed but mobs models are messed up so far I saw that spiders have no legs but the suggestion is that maybe a way to spawn them in with /summon data tags so if this is counted as duplicate alteast let mojang know of the partly suggestion sense it would be good for map makers.
PS: Mobs Spawners are Glitched and Frozen.