spawn_egg can't spawn Giant , SnowMan , VillagerGolem , WitherBoss and EnderDragon

1./give @p minecraft:spawn_egg 1 0 {EntityTag:{id:Giant}}
2./give @p minecraft:spawn_egg 1 0 {EntityTag:{id:EnderDragon}}
3./give @p minecraft:spawn_egg 1 0 {EntityTag:{id:SnowMan}}
4./give @p minecraft:spawn_egg 1 0 {EntityTag:{id:WitherBoss}}
5./give @p minecraft:spawn_egg 1 0 {EntityTag:{id:VillagerGolem}}
6.These can not be used