The designers say it takes about five minutes for a horse to learn how the feeder works, adding that the animal eventually remembers which window to approach, and when, to receive food. The system is programmed so that only one antenna can read each tag, thereby preventing multiple portions being given to the same animal.

"The horses have really calmed down," says Lucas Ahlstrom, an RFIG executive. "They learned the feeding system, and their manners improved. They understand that they will get their food. It's a much more sophisticated way of eating."

A few problems arose during the system's development, however. Designers had to put a sheet-metal covering outside the feeding machine to protect it from the horses' gnawing jaws, so the RFID antennas had to be adjusted to avoid interference with the metal. Designers also made later versions of the feeder more stable after observing, in initial tests, that some horses shook it to extract more food after feeding time.

In addition, decreased daylight does not provide enough solar-generated electricity during the fall and winter. To supplement the power, a tractor can be used to charge the equipment's batteries, or a power line can be run from a nearby facility. Custom-designed software controls the feeding system remotely. The data on every horse is stored on the PC and sent to an external database once per day, via a wireless connection and modem.

Sokymat supplies the tags used in the application, with RFID Systems AB providing the interrogators. Antennas come from various manufacturers.

Once commercially available, a large RFID horse feeder with four windows will sell for about $10,000, while a small one with two windows will roughly cost $5,000. According to Ahlstrom, "ROI can be measured in less wasted food, healthier horses and the extra time the owner and staff have due to the automated feeding process."