Where can I EV train with Hordes in ORAS?

I'm starting to get my competitive Pokemon team together, and would like to EV train using hordes like in XY.

Which routes give the highest Pokemon encounter rate for each stat? Which Pokemon should I be battling?


Most of these Routes have a 100% Encounter rate (or add up to 100%) for their chosen Pokemon and the respective stat:

HP - Rusturf Tunnel (Whismur)

  • Level: 5
  • 1 HP each * 5 = 5 HP

Attack - Mt. Pyre (Shuppet)

  • Level: 15
  • 1 Atk each * 5 = 5 Atk

Defense - Route 111 (Sandshrew)

  • Level: 11
  • 1 Def each * 5 = 5 Def

Special Attack - Route 119 (Oddish) or Route 113 (Spinda)

  • Level: 13 (Oddish), 9 (Spinda)
  • 1 SpA each * 5 = 5 SpA

Special Defense - Route 115 (Swablu)

  • Level: 10
  • 1 SpD each * 5 = 5 SpD

Speed - Route 104 (Zigzagoon, Wingull or Taillow)

  • Level: 2
  • 1 Spe each * 5 = 5 Spe

Notes:

  • Sweet Scent/Honey actually work in overworld Sandstorm/Rain unlike in previous games
  • Shuppet Appears in the Cemetery Area of Mt Pyre
  • Petaburg Woods divides Route 104 in two. (North – Wingull, South – Taillow)
  • Pokérus will double the EVs gained, and stacks with the items below:

  • Macho Brace (Doubles total EVs gained) - Route 111

  • Power Items - Battle Resort
    • Anklet (+4 Speed per Pokemon defeated)
    • Band (+4 Sp. Def per Pokemon defeated)
    • Belt (+4 Defense per Pokemon defeated)
    • Bracer (+4 Attack per Pokemon defeated)
    • Lens (+4 Sp. Attack per Pokemon defeated)
    • Weight (+4 HP per Pokemon defeated)

Sources:

  • Nugget Bridge
  • iDigitalTimes
  • Serebii

For a higher EV yield, you can use the following areas for 2EV points per Pokemon (10 per battle, 20 with Pokerus and 40 with Macho Brace+Pokerus per battle)

Skypillar

  • Ariados - 2 ATK
  • Golbat - 2 SPD

Victory Road

  • Loudred - 2 HP

Route 117

  • Roselia - 2 Sp.ATK

Route 113

  • Skarmory - 2 DEF

And haven't found one with 2 Sp.DEF yet. These aren't guaranteed to be the only hordes on those routes though, just a huge yield imo.

The ones in sky pillar are very common. There is one additional horde of Swablu, but it's uncommon and it usually alternates between Ariados and Golbat. The Loudred in Victory Road seems to be rare, so Whismur might be the better option. Skarmory on Route 113 is relatively rare; almost all the time you get Spinda instead. I haven't tried for Roselia yet: I don't imagine it's that rare since it's abundant on its route in the first place. Hope this helps!