Instructions
Check out Horsetrader.com. Often farms will list used equipment for sale. You can also list your own free want ad for a used hay feeder to maximize your results.
Ask at your local feed store. Employees who work there have a good idea of the local horse community and might know a person who is moving or getting rid of equipment. There is usually a bulletin board at feed stores where people list equipment for sale. Post your own flyer saying "Wanted: Used Horse Hay Feeder," with your contact information. Adding an incentive such as "Top dollar paid" might make someone consider selling.
Visit a local dairy or horse farm. Often these farms will upgrade their equipment or have an unused one around and will be glad to have someone buy the old stuff. If they aren't selling now, you can check back every few months or leave your number for them to contact you in the future.
Check out horse and farm equipment auctions in you area. Auctions usually take place off-season in fairgrounds. This is like a swap meet for the horse owner. Great deals can be had if you have the patience to sit through an auction.
Try your local racetrack or equestrian center. They have equipment that gets overhauled from time to time, and you might hit a goldmine.
How to Buy a Used Horse Hay Feeder
A horse hay feeder is a slotted rack mounted to the wall of a horse's stall, usually made of metal but sometimes made of wood. The feeder keeps hay off the ground and allows hay to be dropped through the open top for the horse to pull through the slots and eat. There are also field hay feeders that are long metal stations built with the same idea in mind--an open top to load in the hay, tapering down to a V-shaped bottom. These hay feeders are larger and designed to feed a group of horses in a field. Finding a used hay feeder isn't difficult--you may have to advertise to let people know you're looking to buy their old rusty one when they're ready to upgrade!