no you have to have undead nightmare..... if u do want the horses you either have to download undead nightmare or buy it at the store.. but i recommend downloading it...
you have to do missions
There is 3, and they are the legendary animals. A Kodiak Bear. (The legendary bear) A Jaguar, (The legendary Jaguar and a Black Wolf. (The legendary Wolf They are only part of the last challenge of hunter.
There is a Secret Achievment in Red Dead Redemption called 'Choo Choo Pony'. the get this achievment you have to capture 100 wild horses and get them hit by a moving train. The reward for this achievment is full Honor and fame as well as a horse mounted Maxim machine gun
find secret holes boss battle 1 2 3 and 4 go to suddend death place without suddendeath mode on. codes for tails nightmare :super
Sabrina's Secret Life - 2003 Midsummer's Nightmare 1-26 was released on: USA: 3 February 2004
Nightmare Next Door - 2011 Burning Secret 2-7 was released on: USA: 4 March 2012
Secret Service Secrets - 2012 Campaign Nightmare 1-2 was released on: USA: 12 February 2012
horses
Secret Mountain Fort Awesome - 2011 Nightmare Sauce 1-5 was released on: USA: 24 October 2011
The Secret World of Alex Mack - 1994 Nightmare in Paradise 3-24 was released on: USA: 27 February 1997
well as you say it is secret so i don't think you will get an answer sorry
feeding their horses alfalfa in the winter