CustomNameVisible won't work!

Hello, For some reason custom name visible won't work for any Animal (e.g. Cows, pigs, horses, chickens, etc.) It does work for non animals (e.g. ArmorStand, Snowball, Fireball, etc.) Here is my command in case if I messed up anything: /summon EntityHorse ~ ~1 ~ {CustomName:"Mat",CustomNameVisible:1,Type:0,SaddleItem:

{id:saddle}

,Variant:256,ArmorItem:

{id:diamond_horse_armor}

}