Quiver

So wait... if there's a Pony!Christmas, wouldn't that imply that some 2000 years before this, Pony!Jesus was born to the Pony!Virgin Mary and a carpenter?

No.  Hearth's Warming Day has a very different mythology behind it.  It celebrates the day when Pegasi, Unicorns, and Earth ponies set aside their differences and began truly working together as friends.

Worldbuilding