The Bug
You can’t use a golden dandelion on a baby zombie horse to stop it from de-aging
Reproduce
Summon a baby zombie horse
/summon minecraft:zombie_horse ~ ~ ~ {Age:-1200}/summon minecraft:zombie_horse ~ ~ ~ {Age:-1200}Use a golden dandelion on it
Observed Result
Nothing happened
Expected Result
It would be consumed
You can, but it has to be tamed using this command:
However, judging by this Bedrock Preview changelog, under “Mobs”:
https://feedback.minecraft.net/hc/en-us/articles/41627058435213-Minecraft-Beta-Preview-26-0-23
“Fixed a bug where baby Zombie Horses would shrink in size when they grew into adult Zombie Horses
They cannot now grow into adult Zombie Horses at all, matching Java Edition”
It seems baby zombie horses (and by extension, baby skeleton horses) aren’t meant to age at all.