Hii, since 1.9 you can't create SpawnEggs(Item) via Durability. It's got a new Tag!
I looked up the Overview and found something. The Object SpawnEgg should actually be ok for that.

itemStack is = new SpawnEgg(EntityType.Creeper).toItemStack(1);

I've added this ItemStack to an Inventory then, but sadly it was displayed as a white SpawnEgg ingame :/

I'm not 100% sure whether this is a bug or whether I'm wrong.