What little I can see of the quarter ponies looks decent. They're in good shape, too. Over thirty, though...
Personally, I think you have the ads themselves down well enough- clean them up, get good pictures, and I can't stress what Endiku said enough: do not lie, but be careful with your wording.
Personally, since there are so many, I would personally go with a Facebook page, in order to have them all in one place in an orderly fashion. Make each one of them a photo album, with both good conformation pictures and some pictures of them moving, etc., and a thorough but simple description of each, including whatever training they've had, their temperaments, their pedigrees (if they're good pedigrees, explain why in a simple way.)
Whatever you do, don't make it sound like you're a cheap car salesman, though, that's a major turn-off for me.
It might also help to make individual ads on Craigslist or some other site for the nicest of them. Mention that there are more available, and to email you for more information if interested in the rest.
Edit- also, like Endiku said, that colt sounds like a crytorchid. Definitely try to get that sorted out with his owner/ a vet, because they can still breed and will still act like stallions. Definitely not good if you're trying to sell him.
Last edited by soenjer55; 05-23-2013 at 05:41 PM.