Apparently 2 horses only need 2 horse shoes.

[MrAnderson]

I had a quest to make enough horse shoes for 2 horses. So, horses have 4 legs each. I crafted 8 horseshoes to turn in for the quest. Nope, wouldn't accept 8 horse shoes. Only accepted 2. Made 6 extra horse shoes for nothing. Thanks game. lol

[SpockEndil]

Each horse shoe is actually a set of horse shoes. I figured that out when I bought four shoes for my horse, and could only equip one. Probably needs some sort of description edit in a future patch.

[Borbarad]

In another Quest you are asked to Smith horseshoes and asking how many gets you the answer. "A horse hast 4 legs, on three of it are already Horseshoes, so how many do you think."

Apparently the Game itself isn't Sure how many Horseshoes one Horseshoe is.

[Asher]

i mean you clearly saw the quest update flash on your screen, open your eyes i guess lol
wait till you find out the horseshoes are not even worth anything and you get them back xD

[EricHVela]

In a game of horseshoes, you get points for being close enough.