Calm down, we all want horse armor.
Frankly, I'd pissed if they put out a DLC and it included horse armor. Of all the things that could be done, armor for an animal who's only decent purpose is to help carry more loot would be the lamest thing ever.
New map areas, questlines, etc. That's what should be in a DLC. Not protective clothing for animals. But if that's the case then I want to be able to craft ebony mail for chickens.